Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for reducing fluid resistance

Abstract

A novel mechanism for reducing boundary layer friction suppresses the effects of uncontrolled fluid turbulence and turbulent layer separation, thereby reducing drag, kinetic energy loss, and fuel consumption in engines and pumps. This application presents and discusses in detail various device shapes and multiple devices that generate an even number of counter-rotating vortices (i.e., tubes) of the desired pure form extending into the flow. Configurations of several devices are proposed for the purpose of reducing drag and fuel consumption, including simulation and experimental results. Other embodiments of the resulting tubes are disclosed for use as stall suppressors on aircraft or ship control surfaces, as dynamic range extenders in wind turbines, and as efficient cooling mechanisms in turbines. Other embodiments focus on appropriately scaling the devices to achieve optimal results on a variety of objects transported in the ocean and water, air and land.

Description

Cross-references to related applications

[0001] This application is a continuation-in-part of U.S. nonprovisional patent application No. 17 / 461,510, filed August 30, 2021, which is a continuation-in-part of international application PCT / US2019 / 047066, filed August 19, 2019, pursuant to 35 U.S.SC §120, which claims the benefit of U.S. Provisional Patent Application No. 62 / 721,191, filed August 22, 2018, and U.S. Provisional Patent Application No. 62 / 822,369, filed March 22, 2019, the entire contents of each of which are incorporated herein by reference. Technical Field

[0002] One embodiment of the invention generally relates to a system in which fluids (i.e., air, gas, various liquids such as water, oil, liquid metals, or compounds) flow along the surface of an object. In one embodiment, the invention particularly relates to a method for reducing boundary layer friction and suppressing the effects of uncontrolled liquid turbulence and turbulent layer separation, thereby reducing drag, kinetic energy loss, and fuel consumption of engines and pumps. In another embodiment, an enhanced heat transfer method is provided that utilizes a specific type of turbulence with minimal separation for turbine blade cooling, thereby increasing turbine inlet temperature and overall efficiency. In yet another embodiment, stall of wings and control surfaces is delayed, improving the agility of ships and aircraft, and reducing fuel consumption through observed drag reduction.

[0003] In another embodiment, reducing hull drag and kinetic energy loss leads to reduced fuel consumption of the ship's propulsion system. In another embodiment, reducing the drag of an aircraft fuselage reduces engine fuel consumption and emissions. In yet another embodiment, reducing the drag of a drone or torpedo reduces fuel consumption and increases operational range, or alternatively, increases the payload of the vehicle. Background Technology

[0004] When an object moves through a fluid, it experiences drag due to internal fluid friction in the layer adhering to and near the object's surface (also known as the boundary layer). Typically, drag increases as the boundary layer transitions from laminar to turbulent flow (a process called the wake). The resulting turbulent vortices are not necessarily attached to the object's surface. As these vortices separate from and deflect from the surface, energy is carried away from the boundary layer, forcing the object to replenish its energy to maintain speed. This process increases the overall drag and energy consumption of the engine propelling the vehicle through the fluid.

[0005] To reduce drag, the boundary layer must be kept in an energetic state while separation is delayed or suppressed. Note that the foregoing statement does not mention turbulent wakes—many drag reduction mechanisms do rely on wakes for effective drag reduction. The following non-limiting examples of techniques borrowed from the marine field help maintain an energetic boundary layer during the motion of an object (Fish, FE, Lauder, GV. 2006. Passive and Active Flow Control by Swimming Fishes and Mammals. Annual Review of Fluid Mechanics. 2006 38:1, 193-224): Heating the surface of an object reduces the boundary layer viscosity, thereby reducing friction and kinetic energy loss (Patent JP3616816B2, Hybrid Technology). Vibrating the surface of an object can effectively “heat” the boundary layer, affecting effective viscosity and friction (Patent JP2006298088A). Introducing air bubbles, even cavitation bubbles that can be sustained long enough for an object to pass through, is another example of effectively reducing viscosity (patents US7874258B2, JP4286313B1, CN106956746A; supercavitation). https: / / en.wikipedia.org / wiki / Supercavitating_torpedo ); Small-scale (submillimeter scale in water, oil, and air), such as the riblets on shark skin, generate small vortices, thereby reducing the effective viscosity near the object with minimal separation and energy dissipation (patents US20110186685A1, US20170081021A1, JP2010023631A; US20100330340A1, a hybrid technology; Bechert DW, Hage W. 2006. Drag reduction with riblets in nature and engineering. In: Flow Phenomena in Nature Volume 2: Inspiration, Learning and Application Design and Nature Vol 8, Vol 2. Wit Press. ISBN 1-84564-095-0). Large nodules on the leading edge of whale fins help maintain the generated turbulent layer attached to the fin, improving stall characteristics (patents KR20100048540A, US20060060721A1, US6431498B1); and Flexible skin, like the skin on a dolphin, can actively deform with turbulence and regulate turbulence, keeping it in a local area to obtain energy benefits (patent US7226484B2).

[0006] While all the techniques mentioned do reduce drag, practical implementation depends on the energy source (in the case of heated objects), the properties of artificial materials (especially flexibility, in the case of dolphin-like skin), and special coating application techniques (in the case of submillimeter ribs, patent WO2018146030A1). Some existing technologies describe adding small dimples, similar to those on a golf ball, to aircraft or ships instead of keeping the surface smooth (Vida N et al., 2003. EP1604122B1). Although it is known that this method of "deformed" surface can promote wake and suppress large separation, thus preventing large energy loss, the cost of manufacturing and maintaining such surfaces may be too high for large-scale application.

[0007] A significant amount of existing technology relates to land vehicles and trailers, and includes various “spoilers” and their configurations. Spoilers do suppress large wakes and control separation at the rear of a vehicle, but they do little to manage high-pressure front-end fluid pressure or reduce drag (including so-called wave drag) generated by sliding within the fluid side boundaries of vehicles, aircraft, and ships.

[0008] Furthermore, in fluid dynamics, as the Reynolds number (Re) increases, drag on an object can be observed to decrease dramatically by a factor of two or more. This is known as the drag crisis. It is important to recognize that the drag crisis primarily arises from the self-organization of fluids within specific types of energy-efficient turbulence, where the turbulence carries away minimal energy. For example, in the case of a sphere, the drag reduction is due to the ability of the early wake to self-organize, such as… Figure 1A As shown. Simulations, which are difficult to perform at high Reynolds numbers, indicate the appearance of four vortices behind the sphere (Hoffman J. 2006. Simulation drag crisis for a sphere using skin friction boundary conditions. Proc. ECCOMAS CFD, 2006). These vortices extend a longer distance behind the sphere and take on a tubular shape. The rotation of the vortices is synchronous, reducing friction at the tube boundary, such as... Figure 1BAs shown in Figure 2. Furthermore, these vortices have a smaller characteristic size compared to the diameter of a sphere. All these observations suggest that only a small fraction of the early wake boundary layer energy is carried away by the vortices. To properly identify the tubular structure in its purest form, it is important to note that the vortices extending with the flow do indeed carry a fine vortex “irregularity” caused by the velocity difference at the fluid boundary moving at relative velocities (Brown G, Roshko A. 1974. On density effects and large structure in turbulent mixing layers. J. Fluid Mech. vol. 64, part 4, pp. 775-816), as shown in Figure 2.

[0009] However, this drag crisis has not yet been exploited in vehicles, ships, and aircraft in an easily manufactured manner to reduce drag.

[0010] Therefore, new methods and devices are needed to reduce drag on vehicles, ships and aircraft, thereby reducing fuel consumption and transportation costs.

[0011] A significant advantage of the large-scale structures proposed in this paper for drag reduction is that they are passive. Furthermore, they allow for easy modification, making the drag reduction method and system applicable to existing ships, vehicles, and aircraft. Note that the large-scale structures discussed are generally different from spoilers. Spoilers are roughly the same size as the object itself, while the large-scale structures discussed in this paper are approximately 1 / 200 to 1 / 50 of the object's characteristic dimensions. For a handysize bulk carrier, these structures would be several meters in size. They are large-scale compared to ribs, which are fractions of the millimeter in size and embedded in a very thin laminar sublayer that is generally independent of the object's size. We refer to the multiple large-scale structures defined in this section as multiple elements, or, in the case of a single large-scale structure, as a single element.

[0012] In order to practically implement drag reduction using components, the following steps need to be taken: Find the optimal placement of the component on the object; Considering the local conditions of the components (i.e., the specific flow conditions at the location where the component is placed), appropriately determine the size of each component; and From a practical implementation perspective, the goal is usually to install the largest possible components to reduce the number of components or groups and to provide a meaningful percentage of drag reduction.

[0013] While some existing techniques provide indications of component size relative to boundary layer thickness, these guidelines are impractical. Considering computational methods, errors in determining boundary layer thickness can range from 100% to 200%, depending on the turbulence model. It is well-known in fluid dynamics that the boundary layer does not exhibit scale effects; therefore, in-situ measurements in the laboratory cannot be translated into guidelines for real-scale component size. In-situ determination of boundary layer thickness at the real scale is only just beginning on commercial vessels (JoRes, a global collaborative research project, 2019). Currently, there is insufficient high-quality data to guide practical implementations of drag reduction using components.

[0014] A new method is needed to determine the optimal dimensions of components. Summary of the Invention

[0015] One embodiment of the present invention provides a method and one or more related devices for reducing fluid resistance. The method provides a device attached to the surface of an object that generates turbulence with minimal separation. In one embodiment, the generated turbulence takes the form of just-contact, counter-rotating vortices extending tubularly along the direction of fluid flow. Various device shapes and multiple devices can be part of this drag reduction method. As resistance decreases, the kinetic energy loss of the object or fluid itself (in the case of fluid flowing through a pipe) also decreases. The energy and fuel required to maintain the motion of the object or fluid are also reduced, thereby lowering the overall operating costs of ships, vehicles, pumps, or aircraft.

[0016] Another embodiment of the invention relies on turbulence generated by one or more surface attachment devices to provide a method for efficient heat exchange. This turbulence exists in the form of just-in-contact vortices, remaining close to the surface with limited separation. It further promotes the downward motion of the fluid toward the surface. The fluid in additional "contact" with the surface participates in heat exchange. The vortices lead to enhanced mixing, thereby "smoothing" the temperature gradient. The enhanced mixing, coupled with the large area covered by the stable counter-rotating vortices, results in efficient heat exchange. The end result is more efficient independent convection cooling, or convection cooling enhancing the effects of other turbine blade internal cooling or film cooling mechanisms. Cooler blades allow for higher turbine inlet temperatures. For every 1% increase in turbine inlet temperature, the turbine's mechanical energy output can increase by 2-3%, thereby improving overall efficiency and reducing turbine operating costs, entirely thanks to better cooling methods and equipment.

[0017] Another embodiment of the invention provides a method for improving stall characteristics of aircraft wings, turbine or propeller blades, and ship or aircraft control surfaces. The method provides a device attached to the surface of an object that generates turbulence with minimal separation. The generated turbulence remains close to the surface and stabilizes the flow. In one embodiment, the device is attached to the leeward side of one or more control surfaces of a wing, blade, ship, aircraft, or glider. In another embodiment, it may be arranged symmetrically on both sides of the control surface. In one embodiment, just-contact counter-rotating vortices induced by the device stabilize the flow, thereby reducing the size of the separation bubble characterizing stall. With the angle of attack and other flow characteristics remaining the same, these devices reduce the overall drag of the surface device and the associated energy required to maintain forward motion. In aircraft, helicopter blades, and ship propellers, this translates to less fuel consumption and lower operating costs. In wind turbines (including vertical wind turbines), stall reduction does indeed increase the turbine's wind range, allowing additional energy to be captured without slowing turbine rotation or structural integrity concerns. Equally important, the agility of the vehicle or vessel is enhanced, allowing the operator to control a greater dynamic range of the vehicle relative to its fluid configuration.

[0018] One embodiment of the present invention provides a method for scaling one or more large-scale surface attachment devices associated with fluid resistance suppression. The method scales the dimensions of the element in relation to the characteristic dimensions of the object, such that the surface attachment element generates turbulence with minimal separation. In one embodiment, this scaling method is applied to elements on the surface of a ship's hull. As drag decreases, the kinetic energy loss of the object also decreases. The energy and fuel required to maintain the object's motion are also reduced, thereby lowering the overall operating costs and emissions of the ship.

[0019] In another embodiment of the invention, appropriately scaled elements are attached to the aircraft fuselage. There, they reduce fuselage drag (typically accounting for about one-third of the total drag of the aircraft), thereby reducing fuel consumption, emissions, and operating costs.

[0020] In another embodiment of the invention, appropriately scaled elements are located on the surface of a torpedo or drone. There, the operating range is extended due to reduced drag. Alternatively, it is conceivable to achieve the same operating range using less fuel. Due to the reduced volume / weight of fuel and batteries, more useful cargo can be transported.

[0021] In another embodiment, appropriately scaled elements are located on the outer surface of land vehicles or cars, trucks, or railcars and locomotives. There, drag is reduced, as are fuel consumption, operating costs, and emissions. Attached Figure Description

[0022] In the accompanying drawings, closely related drawings have the same numbering but different letter suffixes.

[0023] Figure 1A This illustration shows an example of a drag crisis that occurs when a sphere moves through a fluid in the high Reynolds number range. The view is a side view relative to the direction of fluid flow.

[0024] Figure 1B This illustration shows an example of a drag crisis that occurs when a sphere moves through a fluid in the high Reynolds number range. The view is a vertical view relative to the direction of fluid flow.

[0025] Figures 2A-2H An exemplary fine flowline structure is shown in a counter-rotating vortex extending with the flow (i.e., most of the “irregular” flowlines in the tube). A simplified schematic of the actual 3D flow is given in 2D projection to highlight the expected regular fine structure observed in wind tunnel experiments and numerical simulations.

[0026] Figure 3A An embodiment of turbulent wake and turbulent vortex in the case of a dune-shaped turbulence generator is shown, the view being obtained from above and the side.

[0027] Figure 3B An embodiment of a turbulent wake in the case of a dune-shaped turbulence generator is shown, the view being taken from behind the dune (i.e., perpendicular to the direction of fluid flow).

[0028] Figures 4A-4I A family of device elements based on a crescent-shaped dune model is shown. The simulation and experimental results discussed in the Detailed Implementation section refer to the device element in the upper left corner.

[0029] Figures 5A-5I A family of device elements based on a wedge-shaped model is shown. The simulation and experimental results discussed in the Detailed Description section refer to the device element in the upper left corner.

[0030] Figure 6 An embodiment of multiple turbulent wake devices arranged along the flow direction is shown.

[0031] Figure 7 An embodiment is shown in which multiple turbulent wake devices are arranged perpendicular to the flow direction to cover a larger surface area of ​​the object and thereby achieve further drag reduction.

[0032] Figure 8A and Figure 8BThe image shows the vertical fluid motion observed in a wedge flow simulation up to the 20th second of the simulation. For simplified visualization, the upward fluid motion (A) and downward fluid motion (B) are depicted separately. The slice is vertical, with its normal pointing in the flow direction, and is taken approximately 23 units from the wedge apex, with the wedge apex height measured as 1 unit. The Reynolds number is approximately 20,000.

[0033] Figure 9A and Figure 9B The vertical fluid motion observed on a flat surface at the 20th second of the simulation is shown. For simplified visualization, upward motion (A) and downward motion (B) are depicted separately. The slices are vertical, with the normal pointing in the flow direction and at the same distance from the inlet as in Figure 8. The Reynolds number is approximately 20,000.

[0034] Figure 10A and Figure 10B The velocity field of two counter-rotating vortices observed in a wedge flow simulation is shown. The slices are vertical, with the normal pointing in the flow direction. Slice A is located approximately 14 units downstream of the wedge apex (the wedge apex height is measured as 1 unit). Slice B is located approximately 23 units downstream. The simulation times shown are 15 seconds and 20 seconds, respectively. The views show the vortex region maximized and are not drawn to the same scale as Figures 8 and 9. The Reynolds number is approximately 20,000.

[0035] Figure 11A and Figure 11B The streamlines around the NACA 0035 airfoil are shown. The figure illustrates the streamlines of the airfoil with crescent-shaped dunes on its surface (A) and the original smooth surface airfoil (B), respectively. The wing view is taken from the front, with the flow direction away from the observer. The Reynolds number is approximately 3,000,000.

[0036] Figure 12 The NACA 0035 airfoil with dune troughs is depicted for use in flow simulations such as those with a Reynolds number of approximately 3,000,000.

[0037] Figure 13 The change in lift coefficient over time was depicted. The airfoil is NACA 0035, operating at different angles of attack in a flow with a Reynolds number of approximately 3,000,000.

[0038] Figure 14 The drag coefficient was depicted over time. The airfoil was NACA 0035, operating at different angles of attack in a flow with a Reynolds number of approximately 3,000,000.

[0039] Figure 15 The time-averaged lift coefficient (CL) measured for the NACA 0035 simulation setup is depicted.

[0040] Figure 16 The time-averaged drag coefficients measured for various NACA 0035 airfoil simulation settings are depicted.

[0041] Figure 17 The contour lines of fluid velocity with dune troughs are depicted in a flow with an angle of attack of 24 degrees and a Reynolds number of approximately 3,000,000.

[0042] Figure 18 The contour lines depict the fluid velocity of a planar, unmodified (except for rounded edges) NACA 0035 airfoil at an angle of attack of 24 degrees in a flow with a Reynolds number of approximately 3,000,000.

[0043] Figure 19A It describes a large-scale device or component.

[0044] Figure 19B It depicts another large-scale device or element.

[0045] Figure 20 A large-scale installation, appropriately scaled, is depicted in the stern region of a modern container ship hull model.

[0046] Figure 21 A large-scale installation on DARPA Suboff, appropriately scaled, is depicted. Detailed Implementation

[0047] The description of illustrative embodiments according to the principles of the invention is intended to be read in conjunction with the accompanying drawings, which should be considered an integral part of the entire written description. In the description of the embodiments of the invention disclosed herein, any references to directions or orientations are for convenience of description only and are not intended to limit the scope of the invention in any way. Terms such as “lower,” “upper,” “horizontal,” “vertical,” “above,” “below,” “upward,” “downward,” “top,” and “bottom,” and their derivatives (e.g., “horizontally,” “downward,” “upward,” etc.) should be interpreted as referring to the directions described at the time or shown in the drawings discussed. These relative terms are for convenience of description only and do not require the device to be constructed or operated in a particular orientation unless explicitly indicated otherwise. Terms such as “attach,” “fix,” “connect,” “link,” and “interconnect” refer to a relationship in which structures are directly or indirectly fixed or attached to each other, either through an intermediate structure, and to movable or rigid attachments or relationships, unless explicitly stated otherwise. Furthermore, the features and benefits of the invention are illustrated by reference to exemplary embodiments. Therefore, the invention is not expressly limited to these exemplary embodiments, which illustrate a number of possible combinations of non-limiting features that may exist alone or in combination with other features; the scope of the invention is defined by the appended claims.

[0048] This disclosure describes the currently anticipated best mode of implementation. This description is not intended to be construed as limiting, but rather to provide examples of the invention for illustrative purposes only, and to inform those skilled in the art of the advantages and construction of the invention with reference to the accompanying drawings. In the various views of the drawings, the same reference numerals denote the same or similar parts.

[0049] In the case of a sphere, the aforementioned drag crisis is caused by the early wake, and energy can be added to this scenario for effective separation.

[0050] Given the drag crisis described in the literature and the limitations of existing drag reduction technologies, there is a need for a macro-scale, easily manufactured drag reduction structure and method applicable to vehicles and ships in air and in denser environments (i.e., the ocean), in addition to the submillimeter-scale ribs inspired by sharkskin that have been adopted.

[0051] Therefore, in one embodiment, a method for reducing fluid resistance is provided, wherein an object surface (e.g., a vehicle) is provided. At least one device or structure is applied to the object surface, and the device is configured to generate turbulence with minimal fluid separation.

[0052] It should be understood that in discussing objects in this application, different types of objects and object surfaces are referred to in different parts. Therefore, some methods discussed may be more valuable in the context of certain objects (such as vehicles), while other methods may be more valuable in the context of other objects (such as turbine components). However, it should be understood that any methods and apparatus discussed herein can be used in the context of any different objects discussed herein.

[0053] Similarly, a device for reducing drag can be provided, comprising an object having a surface. This object can be, for example, a vehicle body. The surface has at least one means or structure configured to generate turbulence with minimal fluid separation.

[0054] The object can be a sea vehicle, such as a ship, and the device on the object's surface can take the form of a crescent-shaped dune or a wedge, as discussed in more detail below. Alternatively, the object can be a trailer or freight car on a train.

[0055] As described in more detail below, these structures (also referred to herein as devices) can facilitate wake flow while suppressing or completely preventing separation for as long as possible. These structures result in the generation of multiple (including, but not limited to, double-vortex, quad-vortex, etc.) stable, tubular vortices along the flow direction, even at low Reynolds numbers. Other numbers (in addition to double-vortex and quad-vortex), configurations, and variations of tubular vortices are all within the scope of this disclosure.

[0056] In some embodiments, the structure takes the form of a crescent-shaped dune. The leeward side of the dune has two typical extensions (i.e., angles), which do indeed promote turbulence, partially similar to the turbulence observed in spherical drag crises, such as... Figure 3A and Figure 3B As shown, element 200 generates turbulence in the form of counter-rotating tubular vortices 202 and 203 by regulating the flow separation of bubbles 201. The turbulence generated by this element 200 is of a type that does not promote separation, and the laminar flow typically reattaches to the surface at about 10-14 times the dune height. Devices or structures that form crescent-shaped dunes and generate this type of turbulence can be used alone or in combination with other devices to maintain abundant boundary layer energy, keep the laminar velocity distribution close to the surface, and act as drag suppressors. In simulations and wind tunnel experiments, the counter-rotating, just-in-place double vortices (sometimes referred to here as tubes) are clearly visible. Depending on the device that initiates them, the flow above the tubes is 12%-20% faster than the flow at a similar height above a flat surface.

[0057] In addition to the larger flow, the tube, and the accelerated fluid above it, the configuration of two or more devices arranged perpendicular to the flow direction exhibits additional flow stabilizing effects by reducing the effective Reynolds number. The tube extending behind two nearby elements does indeed form a boundary, reducing the characteristic size and the Reynolds number itself. In some embodiments, the object is an aircraft wing, and by placing approximately 100 devices, a Reynolds number reduction of up to two orders of magnitude can be achieved.

[0058] Before discussing specific device configurations, we note that crescent dunes appear to be an optimal, but by no means the only, device. Underdeveloped, bubble-free crescent dunes (i.e., hills) can lead to similar turbulent patterns and thus act as drag suppressors. Other simpler forms, such as those seen in the higher Reynolds number sphere example, can also be used to generate stable, non-separating turbulent flow patterns. Some examples include various wedges, semi-cylinders, hemispheres, various pyramids, cubes, semi-cones, etc.

[0059] Two device shape series are presented. The crescent-shaped dunes can be mathematically described by modeling the "hill" and bubble structure separately. Experimentally, as discussed in existing literature, the vertical, windward profile of the "hill" can be modeled as follows: z(x) ≈ He cosα (x / Lα), where Lα ≡ Le / arccos (2 1 / α), Where α ≈ 3.0 for dunes and α ≈ 1.8 for accumulations. Here, He and Le are the height and length of the “hill”, respectively (Kroy K et al., 2005. The shape of barchan dunes. Journal of Physics: Condensed Matter. Volume 17, Number 14). In 3D, as shown in aerial and space photographs, the longitudinal profile should extend in the y(x) direction and have an asymmetry that makes the leeward side thicker than the windward side. There are several options for modeling this asymmetry. We decided to use the expression derived from our experience.

[0060] For all positive values ​​of x , Negative values ​​are still modeled in the following way: , Bubbles can be modeled using ellipsoids.

[0061] like Figures 4A-4I As shown, several potential forms of device elements can be generated by adjusting parameters and bubble patterns. In some embodiments, the parameters are provided within the following ranges: ; ; ; ;

[0062] Although the crescent dune family offers significant benefits in drag reduction, especially when employing Figure 4F The dune shape shown is complex and difficult to manufacture at low cost. Therefore, we sought different families of device elements. One specific family is the wedge family. Wedges are easy to describe and mass-produce. In OpenSCAD, we wrote: Module wedge ( length, / / Wedge length on the x-axis, the basis for all other dimensions alpha, / / Wedge width, represented as the viewing angle from point 0,0,0; in degrees beta, / / wedge slope angle; degrees tent, / / The width of the wedge apex as viewed from the leading edge of the wedge; in degrees. skew, / / The angle between the trailing edge of the wedge and the vertical line; in degrees flip= false / / Boolean value, determines whether to flip the wedge around the x-axis. ) {height = length tan( beta ); tentScale = abs(tan( tent ) / tan ( alpha / 2 )) / 2.0; linear_extrude( height = height, scale=[0.00001,tentScale], slices= 1000, twist=0, $fn = 100) { halfWidth = length tan(alpha / 2); polygon( points=[ [0, 0], [length, halfWidth], [length, -halfWidth] ]); } } }; In some embodiments, the wedge family is adjusted by adding curvature to the wedge edges to properly "tune" the tube to suppress parasitic turbulence. The result is as follows: Figures 5A-5I As shown, various shapes are available for use in embodiments of the present invention. Therefore, in some embodiments, the structure is not limited to a specific shape or family of shapes. However, in some embodiments, the structure adopts a wedge shape with a curved upper surface, such as... Figures 5A-5I As shown. Such an edge can take the following form: , In this form, the parameters can be chosen empirically to make the adjustment as close as possible to the points (0, 0) and (1, 1). In the intended embodiment, other adjustments and parameter values ​​can be used to adapt to specific types of fluid mixing and the enhanced turbulence required for the embodiment. For example, sigmoid functions, hyperbolic tangents, logarithmic functions, trigonometric functions, exponential functions, polynomials of various orders, nonanalytic functions with self-similarity, and combinations thereof are all possible adjustment functions.

[0063] In some embodiments, the orientation of the device (as seen in the strongly asymmetrical form just now) is important relative to the flow direction. Placing the wedge with its vertical edge as the leading edge (i.e., the edge facing the flow) is suboptimal and does not produce a purely counter-rotating vortex turbulence type. On the other hand, placing the wedge as a slope with its vertical edge downstream does indeed produce turbulence similar to the type observed during drag crises and brings all the benefits therefrom.

[0064] In crescent-shaped and wedge-shaped dune configurations, the size of the device can be adjusted according to the specific implementation plan. For example, a large marine vehicle, such as a ship 100 meters or longer, can be equipped with a device 3-4 meters long. Alternatively, engine components (such as those used in turbines as discussed below) can be equipped with much smaller devices.

[0065] The drag-reduction effect of a single device is amplified by strategically placing a group of devices on an object whose drag is being reduced. Two non-restrictive configuration modes are described.

[0066] Figure 6 The first configuration mode is depicted. As shown, an object surface (the background of the image) is provided, and at least one device 200 is applied to the object surface. The device is in the shape of a crescent-shaped dune. As shown, a second device 200 can be applied along a fluid flow line 300. In the illustrated embodiment, the crescent-shaped dune structure represents the device. It should be understood that the device can take many forms.

[0067] In the first embodiment, such as Figure 6 As shown, devices are typically placed one after another along the fluid flow line, at least five times the height of the device. There is usually a lower limit of five times to reduce the likelihood of generating turbulence with complex flow patterns, which promotes separation and thus suppresses the drag-reducing effect. While there is no upper limit to the distance between devices in this configuration, ideally, it is desirable to cover the object surface with multiple vortices (e.g., double vortices). Considerations for determining the appropriate distance include: laminar reattachment distance, object shape and its influence on the flow, leading and trailing edge areas, and last but equally important, the cost of manufacturing the device and its accessories, and the expected drag reduction.

[0068] Although the devices shown are applied one after another along the fluid flow line, these devices can also be applied perpendicular to the flow line.

[0069] In the second configuration, such as Figure 7As shown, the goal is to cover as much of the object's surface as possible using such a device 200 within a reasonable range to maximize drag reduction. The leading device can be arranged at random locations, configured both normally and tangentially relative to the main flow offset direction. At the leading edge, the distance at which the device is placed on the flow line can also be varied to maximize drag reduction while minimizing manufacturing and maintenance costs.

[0070] The object can be an aircraft, helicopter, aircraft engine, glider, or rocket, in which case the fluid can include air. Therefore, the device can be applied to the surface of any such object. Similarly, the device can be applied to the surface of marine vessels, ships, submarines, torpedoes, or platforms (including single-hull or multi-hull vessels or surfboards), in which case the fluid is water. Similarly, the device can be applied to the surface of automobiles or trailers (including trucks), in which case the fluid includes air. Other vehicles, including locomotives, train carriages, and tank cars / tank cars, are also considered. Similarly, the device can be applied to the surface of pipes, in which case the fluid can be water, oil, liquid metal, chemicals, or gases, etc. Other device and surface configurations are also considered.

[0071] Counter-rotating vortices exhibit important properties. They promote downward flow toward the surface. This is as follows: Figure 8A and Figure 8B As shown, it then flows with fluid above a flat viscous surface (such as...). Figure 9A and 9B (As shown) for comparison. The upward and downward fluid motions are separated and presented separately in... Figure 8A , Figure 9A and Figure 8B , Figure 9B The slices are vertical, with their normals aligned with the flow direction, and are offset from the inlet by the same amount, with snapshots taken at 20 seconds into the simulation. In the wedge case, the slices are located approximately 23 units downstream of the wedge apex, with a apex height of one unit. The fluid is air, and the Reynolds number of the flow is approximately 20,000. The lines in the figure are contour lines of the vertical velocity component. They are equally spaced in terms of vertical velocity increments. This allows for easy visual inspection of the vertical motion, upon which some observations can be made. The flow above the counter-rotating vortex exhibits a downward motion component. This in itself has a stabilizing effect on the flow by suppressing the accumulation of large vortices and their subsequent separation from the surface. In the case of a flat surface, the downward component is not significant in magnitude. There are large upward and downward motions in the counter-rotating vortex region.

[0072] These intense fluid motions (shown almost black due to the high density of contour lines), coupled with the downward stabilizing component above them, are suitable for heat exchange applications, such as in turbines. The vortices themselves exhibit high elasticity and extend very long distances behind the element. Therefore, in some embodiments, a method for improving heat exchange is provided, comprising providing an internal or external object surface and applying at least one means or structure, such as those described above, to the object surface. The means is configured to generate turbulence with minimal fluid separation, wherein the generated turbulence extends directly behind the means (or multiple means, if multiple means are applied) and remains close to the surface. The turbulence close to the surface assists heat exchange in a convective manner.

[0073] Similarly, an apparatus for improving heat exchange can be provided. The apparatus may include the body of an object (e.g., a turbine blade for which heat exchange needs to be improved). The body has an object surface, and at least one device or structure (e.g., those described above) is disposed on the object surface. The device is configured in shape and / or its position to generate turbulence with minimal fluid separation, and the generated turbulence extends directly behind the device and remains close to the surface. The turbulence close to the surface assists heat exchange in a convective manner.

[0074] In such an embodiment, such as Figure 10A and Figure 10B As shown, the vortices remain clearly discernible 14 and 25 height units behind the wedge. Therefore, in one embodiment, they add a calculable, temporally and spatially highly predictable convective component to modern discrete film cooling, full-blade film cooling, full-blade sweating cooling, and older turbine air cooling mechanisms. In another embodiment, one or more elements on the blade improve blade cooling through a purely convective mechanism and operate without needing to be coupled with other forms of cooling. In another embodiment, these elements are placed in the cold air inlet of the air blade to turbulentize the cold airflow, resulting in an approximately 10-20% increase in internal convective cooling efficiency or an approximately 10-20% increase in internal impingement cooling efficiency. In yet another embodiment, these elements are placed on the internal wall surface and turbulentize the internal convection or impingement flow. Other applications of drag crisis-inspired convective heat exchange are also envisioned. This embodiment incorporates elements or devices applied to the turbine blade surface that generate drag crisis-like turbulence at low Reynolds numbers, allowing this turbulence to occur earlier than favorable drag crisis flow conditions.

[0075] Therefore, the fluid may include air, gas, liquefied gas, water, oil, liquid metal or any other fluid, and the object surface may include the surface of an engine inlet or outlet, a turbine inlet or outlet, a pump inlet or outlet, or the surface of a vertical turbine blade, a horizontal turbine propeller or blade, or a helicopter rotor blade.

[0076] Another embodiment of the invention provides a method for improving stall characteristics of aircraft wings, turbine or propeller blades, and control surfaces of ships or aircraft. The method provides an object surface or control surface and applies at least one device to the object surface. The device is configured to generate turbulence with minimal fluid separation. The generated turbulence remains close to the surface and flows steadily. Therefore, the turbulence extends directly behind the device and, with its low dynamic pressure, promotes downward fluid motion toward the surface, thereby stabilizing the flow.

[0077] In some embodiments, a device for improving stall characteristics is provided. The device includes the body of an object (e.g., an airfoil, turbine, or propeller blade, or a ship or aircraft control surface). The body has at least one object surface, and the object surface has at least one means or structure applied thereon. The means is configured in shape, size, and / or location to generate turbulence with minimal fluid separation. This turbulence extends directly behind the means and has low dynamic pressure, promoting downward motion toward the object surface, thereby stabilizing the flow.

[0078] Therefore, in other embodiments of the invention, downward movement toward the surface is utilized to improve stall characteristics of aircraft wings, glider wings, aircraft, glider and ship control surfaces (rudders, elevators, ailerons, stern horizontals, wing sails, etc.), wind turbines, helicopter blades, propellers and turbine blades. As the angle of attack of the wing, blade or control surface increases, a large vortex known as a separation bubble forms on the leeward side. In experiments with a 2-meter-long NACA 0035 airfoil, when six approximately 15-centimeter-long crescent-shaped dune-like elements were placed on the top of the wing (slotted wing), we observed a reduction in the separation bubble size and the absence of backflow. This better organized the flow, with negligible vertical and rearward flow components, such as... Figure 11A The streamlines are shown in the diagram. The flow of the slotted airfoil is compared with... Figure 11B The flow generated by the smooth, unmodified symmetrical NACA airfoil is shown in contrast. The streamlines of the flat airfoil exhibit additional complexity due to the unstable and chaotic flow near the surface. To better understand... Figure 12 The aerodynamic characteristics of a bluff body with sand dunes forming grooves, and the most efficient operating mode related to the fluid transition zone, are compared. The lift and drag coefficients of a smooth-surfaced, round-nosed NACA 0035 airfoil and a round-nosed NACA 0035 airfoil with six sand dunes are plotted. Figure 13 and Figure 14 In the calculations, a variable angle of attack was used, while the Reynolds number remained constant at approximately 3,000,000. The analysis was conducted using various numerical methods. Experiments are strongly recommended to verify the results.

[0079] We can say that the analysis we conducted was relatively conservative. The finite volume method (FVM) based on the gridded RANS equations, where highly nonlinear effects are realized in the calculations using a subgrid turbulence model, deviates significantly from experimental data in some cases due to grid size limitations. According to... Figure 15 The data presented shows that lift loss occurs as the angle of attack increases. At 24 degrees, the average drag coefficient of the slotted wing is lower than that of the clean wing, such as... Figure 16 As shown, this is believed to be due to the expansion of laminar flow in the leading edge of the wing, thus shifting the transition point rearward. Furthermore, the size of the separated bubbles appears to have decreased, as... Figure 17 (Showing slotted wing) and Figure 18 The comparison (showing smooth wings) demonstrates that this helps Figure 16 The drag observed is reduced. In summary, placing components on the wing in the flow transition zone stabilizes the flow and delays stall of the wing and control surfaces, even in suboptimal configurations. Furthermore, in addition to embodiments where the device on the leading edge surface reduces the frontal dynamic pressure with the aid of a tube, collects fluid to suppress its separation, and pushes the transition zone backward, symmetrical embodiments with slots on both surfaces of the wing are also considered.

[0080] In another embodiment, downward fluid motion and the discussed delayed stall are used in wind turbines to overcome stalls experienced due to changes in wind conditions or blade angle of attack, thereby improving the turbine's wind-condition operating range. Delayed stall allows for the application of additional loads to the generator and reduces the risk of turbine shutdown under such larger loads. Delayed stall has a structural stabilizing effect on, for example, vertical Darrieux turbines, which are known to exhibit structural instability due to uneven loading of the blades as they rotate in the wind.

[0081] In another embodiment, one or more elements are placed on the bottom of the surfboard in the form of wedges, crescent-shaped dunes, hill-like protrusions, or ridges. In windsurfing, the athlete bears a tremendous load when the board switches from a non-gliding, boat-like drainage state to a gliding, jet ski state, as she must transmit the required wind power from the sail all the way to the board, especially the tail fin, to allow the board to "glide." Elements on the bottom of the surfboard reduce the load on the athlete by reducing drag, optimally positioning the board in the water, and reducing drainage, ultimately resulting in the board entering a gliding state earlier and more easily. In our experiments using the F2Vegas dual-tail fin board (https: / / www.f2.com / surf / boards.php?da=1829), we produced a stable, easy-to-control board with an early glide capability. These devices effectively cover a speed range of 0-22 knots, operating within the complex triple to quadruple boundaries involving water, air, air-filled water, and the board surface.

[0082] In this document, the terms "large-scale structure" and "component" are used interchangeably. "Attachment," in the context of a component, can also refer to a component being an integral part of the sheet metal used to manufacture the hull (shape). Those skilled in the art will understand that many rolling, stamping, and other methods can make appropriately sized components integral parts of the hull surface.

[0083] Several component shapes were studied. The component shapes studied include... Figure 19A The nodular elements shown and Figure 19B The dune-shaped element shown.

[0084] After extensive research on various object shapes, we concluded that achieving the best possible drag reduction effect with the minimum number of components is possible when the component size is within the range of 0.3% to 3% of the characteristic dimensions of the object. For ocean-going vessels with a total length of 0.3% (LOA), this means that appropriately sized components are within the range of 0.3% × LOA to 3% × LOA. For a typical handysize bulk carrier (LOA of 185 meters), component size can range from 50 cm to 300 cm. The choice of component size for a ship is a matter of convenience in manufacturing or fastening. Similarly, on the hull of a container ship (its bow section is as follows...) Figure 20 As shown), a 175 cm long element is a suitable size.

[0085] DARPA Suboff objects in the drag pool (such as...) Figure 21 Similar results were obtained on models of barges, tankers, bulk carriers, and container ships (as shown).

[0086] Computational fluid dynamics methods have been used to demonstrate similar component scaling on full-size ship types.

[0087] While the invention has been described in detail with respect to several embodiments, it is not intended to limit it to any such details or embodiments or any particular embodiment, but rather to be interpreted with reference to the appended claims in order to provide the broadest possible interpretation in light of the prior art, thereby effectively covering the intended scope of the invention. Furthermore, the foregoing has described the invention according to embodiments conceived by the inventors and for which practicability can be obtained, although unforeseen, non-material modifications may constitute equivalents thereof.

[0088] Attached Figure - Figure Labels 100 - sphere; 101 - Early turbulent wake at high Reynolds numbers; 102 - The vortex tube formed behind the sphere is the main contributor to the sharp decrease in drag under high Reynolds numbers (i.e. drag crisis); 200 - Turbulent wake device, which in this specific case is a dune-shaped 3D form; 201 - Adjustment vortices in dune bubbles; 202 - The vortex tubes formed behind the dunes are the main contributor to drag reduction; 203 - The counter-rotating vortex tubes formed behind the dunes are the main contributor to drag reduction; 300 - Placement of the next turbulent wake device along the flow direction; 400 - Random, normal, and tangential offsets relative to the flow direction when covering the surface of a 2D object to reduce fluid resistance; 500 - Nodular element; 501 - Dune-shaped element; 600 - Container ship hull, bow; 700 - DARPA Suboff, front.

Claims

1. A method for reducing fluid resistance, or obtaining improved stall characteristics and agility, or improving heat exchange, the method comprising: Provide the object surface or control surface; At least one device is applied to the surface of the object; The device is configured to generate turbulence with minimal fluid separation. Among them, the turbulence near the surface assists the heat exchange in a convection manner; The turbulence extends directly behind the device and, with its low dynamic pressure, promotes the downward movement of fluid toward the surface, thereby stabilizing the flow. The resulting turbulence manifests as multiple counter-rotating, just-in-contact vortices, exhibiting a tubular shape along the fluid flow direction; and The resulting turbulence takes the following form: Two counter-rotating vortices that are just in contact appear tubular along the direction of fluid flow. Four opposing rotating vortices, arranged in pairs, appear tubular along the direction of fluid flow, or Multiple pairs of counter-rotating vortices.

2. The method according to claim 1, wherein, The device includes a crescent-shaped dune-like structure, a hill-like structure, or a raised structure.

3. The method according to claim 1, wherein, The device includes various wedges, semi-cylinders, hemispheres, pyramids, cubes, and semi-cones.

4. The method according to claim 1, wherein, The device includes a plurality of devices arranged sequentially along a fluid flow line, wherein applying at least one device includes applying a first of the plurality of devices at a first position on the surface of the object, and applying a second of the plurality of devices at a second position spaced apart from the first position, the length of the interval being greater than five times the height of the first device relative to the surface of the object.

5. The method according to claim 1, wherein, The device includes multiple devices, and the application of the device further includes arranging the device perpendicular to the flow line.

6. The method according to claim 1, wherein, The device includes a plurality of devices, and the application of the device further includes offsetting the plurality of devices relative to the flow and randomly arranging them along the normal and tangential directions relative to each other.

7. The method according to claim 1, wherein, The fluid includes air, and the object surface includes the surface of a vehicle, trailer, container, locomotive, train car, tank car, or tanker, or the object surface includes the control surface of an aircraft, helicopter, aircraft engine, or glider.

8. The method according to claim 1, wherein, The fluid includes water, and the object surface includes the control surface of a ship, vessel, submarine, torpedo, platform, single-hull or multi-hull vessel, or surfboard.

9. The method according to claim 1, wherein, The fluid includes air, gas, liquefied gas, water, oil, liquid metal or other fluids, and the surface of the object includes an engine air intake or exhaust port, a turbine air intake or exhaust port, a pump air intake or exhaust port, or a pipe through which fluid flows.

10. The method according to claim 1, wherein, The fluid includes air, gas, liquefied gas, water, oil, liquid metal or other fluids, and the object surface includes the surface of a vertical turbine blade, a horizontal turbine propeller or blade, or a helicopter rotor blade.

11. A method for appropriately scaling a device and reducing fluid resistance, the method comprising: Provide an object surface, the space enclosed by the object surface being used for transporting goods, personnel or other payloads; At least one device is applied to the surface of the object; Wherein, when the characteristic length of the device is in the range of 0.3% to 3% of the length of the object, the device is configured to generate turbulence with minimal fluid separation.

12. The method according to claim 11, wherein, The surface of the object is the hull of a ship on water.

13. The method according to claim 11, wherein, The surface of the object is that of a barge.

14. The method according to claim 11, wherein, The surface of the object is the fuselage of an aircraft.

15. The method according to claim 11, wherein, The surface of the object is that of a submarine.

16. The method according to claim 11, wherein, The surface of the object is that of a torpedo.

17. The method according to claim 11, wherein, The surface of the object is the fuselage of the drone.

18. The method according to claim 11, wherein, The surface of the object is a car body.

19. The method according to claim 11, wherein, The surface of the object is a truck body.

20. The method according to claim 11, wherein, The surface of the object is a bus.

21. The method according to claim 11, wherein, The surface of the object is a railway vehicle.

22. The method according to claim 11, wherein, The surface of the object is a railway locomotive.

23. The method according to claim 11, wherein, The surface of the object is the rocket fuselage.

24. An apparatus for reducing drag, improving stall characteristics, or improving heat exchange, comprising: a) An object having at least one surface; as well as b) At least one device located on the surface of the object; c) wherein the device is configured to generate turbulence with minimal fluid separation; d) Wherein, the generated turbulence extends directly behind the device and remains close to the surface; e) Among them, turbulence near the surface assists heat exchange through convection; f) wherein the turbulence extends directly behind the device and promotes the downward movement of fluid toward the surface with its low dynamic pressure, thereby stabilizing the flow; g) The resulting turbulence manifests as multiple counter-rotating, just-in-contact vortices, exhibiting a tubular shape along the fluid flow direction; and h) The resulting turbulence takes the following form: Two counter-rotating vortices that are just in contact appear as tubular shapes along the direction of fluid flow, or Four opposing rotating vortices, arranged in pairs, appear tubular along the direction of fluid flow, or Multiple pairs of counter-rotating vortices.

25. The device according to claim 24, wherein, The device includes crescent-shaped, dune-like, hill-like, or protruding structures.

26. The device according to claim 24, wherein, The device includes a plurality of devices arranged sequentially along a fluid flow line, wherein the plurality of devices are spaced apart, and the length of the interval is greater than five times the height of the device relative to the surface of the object.

27. The device according to claim 24, wherein, The device includes a plurality of devices, wherein the devices are arranged perpendicular to the flow line on the surface of the object.

28. The device according to claim 24, wherein, The device includes a plurality of devices, wherein the plurality of devices are located on the surface of the object and are randomly arranged relative to the flow offset and relative to each other along the normal and tangential directions.

29. The device according to claim 24 or 25, wherein, The fluid includes air, and the object surface includes the surface of a vehicle, trailer, container, locomotive, train car, tank car, or tanker, or the object surface includes the control surface of an aircraft, helicopter, aircraft engine, or glider.

30. The device according to claim 24 or 25, wherein, The fluid includes water, and the object surface includes the control surface of a ship, vessel, submarine, torpedo, platform, single-hull or multi-hull vessel, or surfboard.

31. The device according to claim 24 or 25, wherein, The fluid includes air, gas, liquefied gas, water, oil, liquid metal or other fluids, and the surface of the object includes an engine air intake or exhaust port, a turbine air intake or exhaust port, a pump air intake or exhaust port, or a pipe through which fluid flows.

32. The device according to claim 24 or 25, wherein, The fluid includes air, gas, liquefied gas, water, oil, liquid metal or other fluids, and the object surface includes the surface of a vertical turbine blade, a horizontal turbine propeller or blade.

33. A device for reducing resistance, comprising: a) An object having at least one surface; as well as b) At least one device located on the surface of the object; c) wherein, when the characteristic length of the device is in the range of 0.3% to 3% of the length of the object, the device is configured to generate turbulence with minimal fluid separation.

34. The device according to claim 33, wherein, The surface of the object is the hull of a ship on water.

35. The device according to claim 33, wherein, The surface of the object is that of a barge.

36. The device according to claim 33, wherein, The surface of the object is the fuselage of an aircraft.

37. The device according to claim 33, wherein, The surface of the object is that of a submarine.

38. The device according to claim 33, wherein, The surface of the object is that of a torpedo.

39. The device according to claim 33, wherein, The surface of the object is the fuselage of the drone.

40. The device according to claim 33, wherein, The surface of the object is a car body.

41. The device according to claim 33, wherein, The surface of the object is a truck body.

42. The device according to claim 33, wherein, The surface of the object is a bus.

43. The device according to claim 33, wherein, The surface of the object is a railway vehicle.

44. The device according to claim 33, wherein, The surface of the object is a railway locomotive.

45. The device according to claim 33, wherein, The surface of the object is the rocket fuselage.

46. ​​A method for reducing fluid resistance, the method comprising: Provide the object surface; At least one device is applied to the surface of the object; The device is configured to generate turbulence with minimal fluid separation.

47. A method for improving heat exchange, the method comprising: Provide the internal or external object surface; At least one device is applied to the surface of the object; The device is configured to generate turbulence with minimal fluid separation; The resulting turbulence extends directly behind the device and remains close to the surface; and Among them, turbulence near the surface assists heat exchange through convection.

48. A method for obtaining improved stall characteristics and agility, the method comprising: Provide the object surface or control surface; Apply at least one device to the surface of the object or the control surface; The device is configured to generate turbulence with minimal fluid separation; and The turbulence extends directly behind the device and, with its low dynamic pressure, promotes the downward movement of fluid toward the surface, thereby stabilizing the flow.

49. The method according to claim 46, 47 or 48, wherein, The resulting turbulence takes the form of multiple counter-rotating, just-in-touch vortices, which appear tubular along the direction of fluid flow.

50. The method of claim 49, wherein, The resulting turbulence takes the following form: Two counter-rotating vortices that are just in contact appear as tubular shapes along the direction of fluid flow, or Four opposing rotating vortices, arranged in pairs, appear tubular along the direction of fluid flow.

51. The method according to claim 46, 47 or 48, wherein, The device includes a crescent-shaped dune-like structure.

52. The method according to claim 46, 47 or 48, wherein, The device includes a hill-shaped or protruding structure.

53. The method according to claim 46, 47 or 48, wherein, The device includes various wedges, semi-cylinders, hemispheres, pyramids, cubes, and semi-cones.

54. The method according to claim 46, 47 or 48, wherein, The device comprises multiple devices arranged sequentially along the fluid flow line.

55. The method according to claim 54, wherein, The application of at least one device includes applying a first of the plurality of devices at a first position on the surface of the object, and applying a second of the plurality of devices at a second position spaced apart from the first position, the distance between the two positions being greater than five times the height of the first device relative to the surface of the object.

56. The method according to claim 46, 47 or 48, wherein, The device includes multiple devices, and the application of the device further includes arranging the device perpendicular to the flow line.

57. The method according to claim 46, 47 or 48, wherein, The device includes a plurality of devices, and the application of the device further includes offsetting the plurality of devices relative to the flow and randomly arranging them along the normal and tangential directions relative to each other.

58. The method according to claim 46 or 48, wherein, The fluid includes air, and the object surface includes control surfaces of an aircraft, helicopter, aircraft engine, or glider.

59. The method according to claim 46 or 48, wherein, The fluid includes water, and the object surface includes the control surface of a ship, vessel, submarine, torpedo, platform, single-hull or multi-hull vessel, or surfboard.

60. The method of claim 46, wherein, The fluid includes air, and the object surface includes the surface of a vehicle, trailer, container, locomotive, train car, tank car, or tanker.

61. The method according to claim 46, 47 or 48, wherein, The fluid includes air, gas, liquefied gas, water, oil, liquid metal or other fluids, and the object surface includes an engine air intake or exhaust port, a turbine air intake or exhaust port, a pump air intake or exhaust port.

62. The method according to claim 46, 47 or 48, wherein, The fluid includes air, gas, liquefied gas, water, oil, liquid metal or other fluids, and the object surface includes the surface of a vertical turbine blade, a horizontal turbine propeller or blade, or a helicopter rotor blade.

63. The method according to claim 46, 47 or 48, wherein, The fluid includes water, oil, liquid metal, chemicals, or gas, and the surface of the object includes the surface of a conduit through which the fluid flows.

64. A device for reducing resistance, comprising: a) An object having at least one surface; as well as b) At least one device located on the surface of the object; c) wherein the device is configured to generate turbulence with minimal fluid separation.

65. An apparatus for improving heat exchange, comprising: a) An object having at least one surface; as well as b) At least one device located on the surface of the object; c) wherein the device is configured to generate turbulence with minimal fluid separation; d) Wherein, the generated turbulence extends directly behind the device and remains close to the surface; and e) In this process, turbulence near the surface assists heat exchange through convection.

66. An apparatus for improving stall characteristics, comprising: a) An object having at least one surface; as well as b) At least one device located on the surface of the object; c) wherein the device is configured to generate turbulence with minimal fluid separation; and d) Wherein, the turbulence extends directly behind the device and promotes the downward movement of fluid toward the surface with its low dynamic pressure, thereby stabilizing the flow.

67. The device according to claim 64, 65 or 66, wherein, The resulting turbulence takes the form of multiple counter-rotating, just-in-touch vortices, which appear tubular along the direction of fluid flow.

68. The device according to claim 64, 65 or 66, wherein, The resulting turbulence takes the following form: Two counter-rotating vortices that are just in contact appear as tubular shapes along the direction of fluid flow, or Four opposing rotating vortices, arranged in pairs, appear tubular along the direction of fluid flow.

69. The device according to claim 64, 65 or 66, wherein, The device includes a crescent-shaped dune-like structure.

70. The device according to claim 64, 65 or 66, wherein, The device includes a hill-shaped or protruding structure.

71. The device according to claim 64, 65 or 66, wherein, The device includes various wedges, semi-cylinders, hemispheres, pyramids, cubes, and semi-cones.

72. The device according to claim 64, 65 or 66, wherein, The device comprises multiple devices arranged sequentially along the fluid flow line.

73. The device according to claim 72, wherein, The plurality of devices are arranged at intervals, with the length of the interval being greater than five times the height of the device relative to the surface of the object.

74. The device according to claim 64, 65 or 66, wherein, The device includes a plurality of devices, wherein the plurality of devices are arranged perpendicular to the flow line on the surface of the object.

75. The device according to claim 64, 65 or 66, wherein, The device includes a plurality of devices, wherein the plurality of devices are located on the surface of the object and are randomly arranged relative to the flow offset and relative to each other along the normal and tangential directions.

76. The device according to claim 64 or 66, wherein, The fluid includes air, and the object surface includes control surfaces of an aircraft, helicopter, aircraft engine, or glider.

77. The device according to claim 64 or 66, wherein, The fluid includes water, and the object surface includes the control surface of a ship, vessel, submarine, torpedo, platform, single-hull or multi-hull vessel, or surfboard.

78. The device according to claim 64, wherein, The fluid includes air, and the object surface includes the surface of a vehicle, trailer, container, locomotive, train car, tank car, or tanker.

79. The device according to claim 64, 65 or 66, wherein, The fluid includes air, gas, liquefied gas, water, oil, liquid metal or other fluids, and the object surface includes an engine air intake or exhaust port, a turbine air intake or exhaust port, a pump air intake or exhaust port.

80. The device according to claim 64, 65 or 66, wherein, The fluid includes air, gas, liquefied gas, water, oil, liquid metal or other fluids, and the object surface includes the surface of a vertical turbine blade, a horizontal turbine propeller or blade.

81. The device according to claim 64, 65 or 66, wherein, The fluid includes water, oil, liquid metal, chemicals, or gas, and the surface of the object includes the surface of a conduit through which the fluid flows.

82. A vehicle comprising: A main body with an object surface; Multiple structures arranged on the surface of the object; Each of the plurality of structures takes the form of a crescent-shaped dune or a wedge.

83. The vehicle according to claim 82, wherein, Each of the plurality of structures is wedge-shaped with a curved upper surface, the wedge surface and edges being described by the following functions as adjustment functions: sigmoid functions, hyperbolic tangent functions, logarithmic functions, trigonometric functions, exponential functions, polynomials of various orders, nonanalytic functions with self-similarity, and combinations thereof.

84. A turbine blade, comprising: Object surface; Multiple structures arranged on the surface of the object; Each of the plurality of structures takes the form of a crescent-shaped dune or a wedge.

85. The turbine blade according to claim 84, wherein, The plurality of structures generate a convective cooling component.

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