Cavity acoustic tone suppression

Abstract

A vehicle is provided. The vehicle comprises an outer panel, a cavity exposed to the outside atmosphere of the vehicle, and a spoiler positioned close to the front edge of the cavity, the front edge being relative to the actual or intended flow direction of the fluid over the cavity. The spoiler comprises a bottom surface, a rear surface, and a front surface, wherein, in use, the front surface faces the fluid coming from the flow direction, the bottom surface faces the outer panel, and at least one support member for raising the spoiler above the outer panel of the vehicle such that a gap is provided between the outer panel and the bottom surface of the spoiler, wherein the outer panel, the bottom surface, and the rear surface are arranged such that the fluid passing through the gap is carried in and increases the height of the shear layer above the cavity.

Description

Technical Field

[0001] The present invention relates to a vehicle having a cavity and a spoiler for reducing acoustic noise within the cavity. Exemplary vehicles include aircraft.

Background Art

[0002] When a cavity is moving through a surrounding fluid, for example, when an aircraft bay is moving through air, a shear layer is formed between the moving surrounding air and the stationary air within the cavity (from a reference point of the aircraft). The shear layer is a thin region where vorticity with a large change in the tangential velocity component is concentrated, is positioned across the top of the cavity, and separates the high-speed flow and the low-speed flow. Vortices are released from the leading edge of the cavity, grow as they progress downward through the shear layer, collide with the rear (aft) wall of the bay, and result in the emission of noise. Also, sound waves return upstream inside the cavity.

[0003] When the pressure of the sound waves fluctuates, it can result in either the release of vortices from the cavity lip at the leading edge or an increase in the growth rate of the vortices, so that a series of vortices are formed below the shear layer at a preferred rate related to the frequency of the upstream sound waves. The vortices grow into large-scale structures as they propagate downstream in the shear layer and then collide with the rear (aft) wall of the cavity at a characteristic rate. This results in the generation of acoustic noise at a characteristic rate that can be described as an acoustic tone of a characteristic frequency.

[0004] Similar problems are seen in other types of vehicles such as high-performance cars having a roof or window that is opened when traveling at speed, or marine vessels having an open hatch with a high wind speed at impact.

[0005] Therefore, there is a need for a lightweight mitigation mechanism for reducing acoustic noise in cavities through which fluid passes.

[0006] In aircraft, spoiler structures are known to be used to divert airflow over and beyond cavities, that is, over any boundary layer or expected shear layer, in order to prevent the effects described above from occurring.

[0007] In other words, existing standard mitigation measures aim to provide a form of noise suppression by diverting the shear layer away from the cavity, thickening (diverging) the shear layer, or generating multiple small-scale turbulences that result in multiple smaller vortices within the shear layer. In this way, the formation of large vortices in the shear layer, which is part of the tone generation process, is inhibited. One way to prevent small vortices from forming larger vortices is to increase the thickness of the shear layer, because the smaller vortices move at different speeds, which in turn reduces temporal coherence and inhibits the formation of larger vortices. Various mitigation / spoiler options have different mechanisms that help reduce noise and tone resonance.

[0008] The inventors have realized how to improve such spoilers in order to further reduce acoustic noise within the cavity. [Overview of the project]

[0009] According to the first aspect, a vehicle, The exterior panels and, The cavity exposed to the outside air of the vehicle, A spoiler positioned close to the front edge of the cavity and The front edge is relative to the actual or intended flow direction of the fluid over the cavity, and the spoiler is The bottom surface, rear surface, and front surface, wherein, during use, the front surface faces the fluid coming from the direction of flow, and the bottom surface faces the outer plate. At least one support member for raising the spoiler above the outer panel of the vehicle, such that a gap is provided between the outer panel and the lower surface of the spoiler, wherein the outer panel, lower surface, and rear surface are arranged such that fluid passing through the gap is carried in and the height of the shear layer above the cavity, A vehicle equipped with this feature will be provided.

[0010] Advantageously, the spoiler is positioned to capture fluid particles flowing directly beneath it, pull them upward, and further extend the height of the shear layer.

[0011] The support member may include a hinge for causing the spoiler to rotate relative to the vehicle. The support member may include a sliding mechanism for raising the spoiler away from the outer panel. The support member may be coupled to the inner surface of a cavity.

[0012] The vehicle may have a secondary cavity located in front of the main cavity, and the spoiler is positioned to retract into the secondary cavity when not in a deployed configuration.

[0013] The rear surface may have a curved portion. The rear surface may have a vertical portion and a curved portion. The curved portion may have a concave curve with respect to the actual or intended flow direction. The tangent to the angle of curvature at any point along the curved portion may be greater than 0 degrees and less than or equal to 15 degrees.

[0014] The rear and bottom surfaces may be components of a single surface.

[0015] The rear surface may have a flat section angled acutely with respect to the horizontal plane. The angle of the rear surface with respect to the horizontal may be greater than 0 degrees and less than or equal to 15 degrees.

[0016] The outer plating on which the spoiler is raised above it may be angled with respect to the horizontal plane so that its height increases in the direction of the flow. The outer plating on which the spoiler is raised above it may be curved so as to form an incline with respect to the incoming flow.

[0017] The cavity may be a payload bay for housing a payload. The cavity may be a rotatable payload bay configured to rotate so that the payload is exposed to the ambient atmosphere.

[0018] The vehicle can be an aircraft, and the fluid can be air. Alternatively, the vehicle can be a car, and the fluid can be air. Also alternatively, the vehicle can be a watercraft, and the fluid can be air. Also alternatively, the vehicle can be a watercraft, and the fluid can be water.

[0019] Embodiments of the present invention are now described by way of example only with reference to the drawings.

Brief Description of the Drawings

[0020] [Figure 1] Schematic perspective view of a payload bay module having a spoiler (not to scale). [Figure 2] Schematic perspective view of a prior art spoiler (not to scale). [Figure 3] Schematic perspective view of a spoiler according to an embodiment (not to scale). [Figure 4] Schematic perspective view of a spoiler according to another embodiment (not to scale). [Figure 5] Schematic perspective view of a spoiler according to another embodiment (not to scale). [Figure 6a] Schematic side view of an aircraft having a payload bay module as shown in FIG. 1 in a closed configuration (not to scale). [Figure 6b] Schematic side view of an aircraft having a payload bay module as shown in FIG. 1 in an open configuration (not to scale).

Modes for Carrying Out the Invention

[0021] Relative terms such as horizontal and vertical, top and bottom, above and below, front and rear are used herein solely for the convenience of referring to the figures, and it will be recognized that these terms are not in themselves limiting. Instead of truly horizontal and vertical, top and bottom, etc., any two different directions or positions, etc. can be implemented. In particular, for convenience, in FIG. 1, the cavity is shown as opening at the top of the page, and thus, for convenience, the word "top" is used to mean the opening of the cavity, and the word "above" is used to mean being further away from the cavity. However, the present disclosure also refers to, for example, a cavity positioned directly below an aircraft wing or fuselage, i.e., upside down from that shown in FIG. 1, and it will be recognized that the use of the explanation of the word "top" still refers to the opening of the cavity, and the use of the explanation of the word "above" still refers to being away from the cavity.

[0022] Generally, the present disclosure relates to methods and apparatuses for suppressing detrimental aerodynamic acoustic effects such as acoustic tones and / or resonances and / or noises and / or other acoustic tone effects in a cavity when the cavity is moving relative to ambient fluid such as air. The present disclosure relates particularly, but not limited to, such methods and apparatuses for vehicle cavities. Exemplary vehicles include aircraft, and thus, exemplary cavities include bays such as weapon bays and landing gear bays. The apparatus includes a leading edge cavity mitigation device (i.e., a spoiler) having a front face and a rear face, both the front face and the rear face having non-vertical components. The placement and shape of the spoiler tend to optimize the jet flow across the space between the lower surface (i.e., the bottom surface) of the spoiler and the outer skin of the vehicle (or the surface to which the spoiler is attached), thereby assisting the growth of the shear layer over the resulting cavity opening.

[0023] Figure 1 is a perspective view of a bay module 100 (specifically, a payload bay module) according to an embodiment. Here, the bay module 100 has a structure having a cavity 2 (also known as a bay) inside. It will be understood that the present invention is applicable not only to those forming part of individual modules, but also to any device having a cavity, i.e., any bay. For example, the cavity 2 may be a recess or depression in the main structure of a vehicle. As will be described later, the walls forming the cavity 2 may, therefore, be an integral part of the vehicle itself.

[0024] Cavity 2 may be for housing a payload such as a missile or camera system. When in use, cavity 2 may be empty. Cavity 2 may contain a unit inside, for example, a rotating bay module 100 as described herein. The payload may be a deployable payload or combat equipment released from cavity 2.

[0025] Cavity 2 is defined by the inner surfaces of walls 8, 10, and 12 of bay module 100. During use, fluid (e.g., air) passes through cavity 2, and therefore the main flow of the fluid acts in the opposite direction to the actual or intended direction of movement of cavity 2 (i.e., flow direction 3). When fluid passes through cavity 2, it tends to generate unsteady flow structures that are difficult to simulate.

[0026] The bay module 100 comprises a front wall 8, a rear wall 10, and two side walls 12a, 12b (collectively 12) defined with respect to the actual or intended main flow direction 3. In the exemplary embodiment, the bay module 100 comprises a rectangular planar base 1 and has a rectangular opening (i.e., aperture).

[0027] Therefore, when viewed from above, cavity 2 has a rectangular cross-section. However, it will be recognized that cavity 2 may have alternative shapes such as a circular, semicircular, or triangular cross-section.

[0028] The side walls 12 and rear wall 10 are perpendicular to the planar base (i.e., vertical) 1, and the front wall 8 is angled to the base 1 such that the opening has a larger circumference than the outer circumference of the base 1. In other embodiments, one or more of the walls 8, 12, and 10 may be angled such that the opening has a larger circumference than the outer circumference of the base 1. Again in other embodiments, all of the walls 8, 10, and 12 may be substantially vertical.

[0029] However, these specific cavity details are not mandatory, and in other embodiments, any other cavity shape may exist. For example, it is not necessary to have only four walls 8, 10, 12a, and 12b. Walls 8, 10, and 12 do not need to be straight or perpendicular. Cavity 2 may be defined by one or more walls forming a curved or partially curved perimeter relative to cavity 2. The perimeter may have an irregular shape. One or more walls may be inclined. The base 1 and / or one or more walls may be wavy or inclined, etc. However, the suppression will tend to be stronger the more linearly the front edge 14 is defined or present (compared to the actual or intended flow direction 3).

[0030] The opening of cavity 2 may be formed by the outer skin of a vehicle, such as an aircraft. In other words, cavity 2 may not have walls 8, 10, 12 on its own, and may be formed integrally with the vehicle. In other words, the outer skin of the vehicle provides a surface on which gaps or large changes in orientation on its surface form the opening of cavity 2.

[0031] Each of the walls 8, 10, and 12 has an upper surface. The inner edges of the upper surfaces (i.e., the front edge 14, the rear edge 16, and the lateral (side) edges 18a, 18b (collectively referred to as 18)) define the lip of the cavity 2, i.e., the edges 14, 16, and 18 of the cavity 2 define the opening. The upper surfaces of each of the walls 8, 10, and 12 are substantially the same plane.

[0032] In the illustrated embodiments, the side wall 12 is shown to be longer than the front wall 8 and the rear wall 10, but this may not be the case in other embodiments. For example, the cavity 2 may be wider in the transverse (i.e., perpendicular) direction than in the direction of the main fluid flow 3. In other words, the transverse edge 18 may be shorter than the front edge 14 and the rear edge 16.

[0033] The bay module 100 is a rotating bay having a rotation axis 4. In the illustrated embodiment, the rotation axis 4 is aligned with the central longitudinal axis of the bay module 100. In other embodiments, the bay module 100 may rotate about an axis offset to one side of the bay module 100, for example, along the lateral edge 18 of the cavity 2.

[0034] The bay module 100 is driven to rotate around a pivot point 6 through which the rotation axis 4 passes. As illustrated in Figures 6a and 6b, the bay module 100 may be driven to rotate by a motor 9. The bay module 100 rotates to expose the cavity 2 to ambient flow (e.g., ambient airflow).

[0035] The spoiler 7 is positioned in front of the cavity 2 in the path of the main fluid flow direction 3. When in use, the spoiler 7 extends away from the cavity 2 into the surrounding flow, such as the airflow.

[0036] The upper edge of the spoiler 7 is shown as linear and parallel to the front edge 14 of the cavity 2 (i.e., without inclination or sloping downwards with respect to the plane of the surface to which the flow partition is attached). In another embodiment, the height of the spoiler 7 may vary along its length. The maximum height (i.e., vertical spread) of the spoiler 7 may be selected according to the geometric shape of the cavity 2. However, the height of the spoiler 7 is approximately 3 cm to 20 cm.

[0037] The spoiler 7 can be molded to match the shape of the front edge 14 of the cavity 2. For example, if the cross-section of the cavity 2 is circular, the spoiler 7 can be curved along its length. The spoiler 7 can also be curved along its length even if the front edge 14 is straight.

[0038] The shape of spoiler 7 in the side view will be discussed in more detail later with reference to Figures 2-5.

[0039] There may be more than one spoiler 7 along the front side of cavity 2. Multiple spoilers 7 may be coaxial with each other. In other words, spoiler 7 may consist of a series of discontinuous spoilers 7. Multiple spoilers 7 may be arranged in a "V" shape.

[0040] The spoiler 7 is suspended above the upper surface of the front wall 8 such that its lower surface is exposed to the airflow. In the illustrated embodiment, the spoiler 7 is connected to the front wall 8 by a pair of legs 5. However, it will be recognized that any structural arrangement may be used to create a gap between the spoiler 7 and the upper surface of the front wall 8. As will be discussed later, the spoiler 7 may be suspended above the upper surface of the front wall 8 by a member connecting the spoiler 7 to the inside of the cavity 2, for example, to the inside of the front wall 8.

[0041] As described above, in an alternative embodiment, the front wall 8 may be absent, in which case the surface defining the edge of the opening of the cavity 2 is a part of the vehicle, for example, the vehicle's outer panel. The spoiler 7 is suspended above this surface, in front of the cavity 2.

[0042] The vehicle body or surface directly beneath the spoiler 7 may be flat and parallel to the horizontal plane (assuming this is the flow direction 3 during use). Alternatively, the body or surface may be contoured to increase the mass flow between the underside (i.e., bottom) of the spoiler 7 and the body / surface. In other words, the upper surface of the vehicle body or front wall 8 may be curved upward to exhibit an incline with respect to the incoming fluid flow, with increasing height toward the cavity 2. The body / surface may be flat, but may be inclined with respect to the horizontal plane, with increasing height toward the cavity 2.

[0043] The spoiler 7 can be made from any material strong enough to withstand high-speed free-flow and high noise. For example, the spoiler 7 can be made from a composite material such as titanium or carbon fiber. Alternatively, the spoiler 7 can be formed from plastic or aluminum. The spoiler 7 can be made from the same material as the body panel of the vehicle to which it is attached. The spoiler 7 can be formed from gauze or mesh.

[0044] In one embodiment, the spoiler 7 comprises at least one hinge, which is coupled to the inner surface of the front wall 8. In an alternative embodiment, the hinges are coupled to both sides of the spoiler 7 and to the inner surface of the front region of the side wall 12.

[0045] The hinge (or multiple hinges) is configured to allow the spoiler 7 to pivot about an axis so that in the retracted configuration the spoiler 7 does not substantially protrude into the surrounding flow (i.e., the spoiler 7 is located inside the cavity 2), and in the deployed configuration the spoiler 7 extends into the surrounding flow, as shown in Figure 1.

[0046] In other words, the suppression system may include a hinge coupled to the spoiler 7 to allow the spoiler 7 to rotate relative to the cavity 2. Examples of such hinges include offset hinges or leaf hinges. Thereafter, when in use, the spoiler 7 is configured to rotate into the airflow away from the body of the vehicle.

[0047] For example, cavity 2 could be an aircraft's weapons bay, and spoiler 7 could be translated from a first storage position inside cavity 2 to a second deployed position in the airflow when the weapons bay door is open.

[0048] The spoiler 7 may instead be slidably mounted on the inner surface of the cavity front wall 8 or side wall 12, so that the spoiler 7 can slide to protrude into the surrounding flow.

[0049] The hinge or sliding mechanism may be motorized, mechanically actuated by the movement of the door covering the cavity 2, or spring-loaded.

[0050] Instead of being rotatably or slidably coupled to one or more walls of cavity 2, spoiler 7 may be rotatably or slidably coupled to a second cavity located in front of cavity 2. In other words, spoiler 7 may be housed within its own cavity 2 on the surface of the vehicle or bay module 100.

[0051] In some embodiments, the spoiler 7 is perforated, but in other embodiments, the surface of the spoiler 7 is completely seamless.

[0052] In the illustrated embodiment, the spoiler 7 extends across the entire width of the cavity 2. However, this is not necessarily required, and in other embodiments, the spoiler 7 may extend across only a portion of the width of the cavity 2, which would preferably be at least half the width of the cavity 2, and more preferably at least three-quarters (3 / 4) of the width of the cavity 2.

[0053] Instead of being positioned perpendicular to the flow direction 3, the spoiler 7 may be angled with respect to the flow direction 3 (in the vertical plane as shown in the figure). In this embodiment, the front surface of the spoiler 7 is acute with respect to the impacting flow direction 3. In other words, the first region of the front surface of the spoiler 7 is located closer to the front of the cavity 2 than the second region of the front surface of the spoiler 7. In particular, if the spoiler 7 has a wavy front surface, the longitudinal axis passing through each end of the spoiler 7 may form an obtuse angle with respect to the impacting flow direction 3.

[0054] The spoiler 7 can be positioned upstream of the front edge 14 (i.e., in front of the cavity 2) at any position close to the front edge 14. This position can be any distance from the front edge 14 that is less than or equal to half the distance between the front edge 14 and the rear edge 16. However, preferably, the spoiler 7 is positioned upstream of the front edge 14 at a distance of 0.2 × the distance between the front edge 14 and the rear edge 16 (i.e., the length of the cavity 2), more preferably at a distance of 0.1 × the length of the cavity 2, and even more preferably at a distance of 0.05 × the length of the cavity 2. In yet another embodiment, the spoiler 7 is positioned directly above the front edge 14 such that the vertical plane passing through the front edge 14 is coplane with the vertical plane passing through the rearmost part of the spoiler 7.

[0055] The spoiler 7 functions when it is possible for fluid to flow directly beneath its underside. The spoiler 7 tends to function most favorably when there is a relatively small gap between its underside and the surface to which it is attached (i.e., the aircraft's outer skin). However, in an alternative embodiment, the spoiler 7 is positioned downstream of the leading edge 14 (i.e., above the cavity 2) so that fluid can flow between the base 1 and the underside of the spoiler 7.

[0056] Here, the spoiler 7 is positioned closer to the front edge 14 than to the rear edge 16. More specifically, in this embodiment, the spoiler 7 is positioned such that the distance of the spoiler 7 from the front edge 14 is equal to 0.02 to 0.07 × the total distance between the front edge 14 and the rear edge 16 (i.e., the total length of the cavity 2). Preferably, this distance is 0.05 × the total length of the cavity 2.

[0057] Spoiler 7 plays a role in increasing the thickness of the shear layer. The shear layer is the region between the line representing the top of spoiler 7 (i.e., the point furthest from cavity 2) and the line representing the bottom of spoiler 7 (i.e., the point closest to cavity 2). The thickness of the shear layer at any point along cavity 2 is correspondingly the distance between the top and bottom of the shear layer.

[0058] Here, the shape of spoiler 7, which will be described in more detail with reference to Figures 2-5, tends to help raise the shear layer further up the cavity 2 than a typical spoiler, i.e., giving the shear layer a greater reach and reducing its impact on the equipment and payload inside the cavity 2. In the subsonic Mach region, the fluid can travel through the gap between spoiler 7 and the surface around the cavity 2 (e.g., the vehicle's outer shell). Here, as will be described with reference to Figure 2, the design of prior art spoilers in front of the opening of the cavity 2 is not optimized for this fluid flow to aid in the growth of the shear layer.

[0059] Figure 2 illustrates a typical prior art spoiler 7a, as may be found on existing cars and other vehicles. Figures 3–5 illustrate spoilers 7b–d according to embodiments. Spoilers 7a–d may be used to replace spoiler 7 shown in Figure 1.

[0060] In all embodiments, the spoiler 7 comprises a front surface 70 and a rear surface 76. The front surface 70 is the surface facing the flow direction 3, i.e., the direction of travel of the vehicle. The rear surface 76 faces toward the cavity 2. Some embodiments include a bottom surface 72. The bottom surface 72 is the surface facing the upper surface of the vehicle's outer panel or the front wall 8 of the bay module 100.

[0061] In the illustrated embodiment, the front surfaces 70 of the spoilers 7a-d are provided with concave surfaces that form a slope for the incoming fluid flow. However, in a less preferred embodiment, the front surfaces 70 may be flat. The front surfaces 70 may be positioned vertically.

[0062] Several embodiments, and all of the embodiments described herein, include a right side 74a and a left side 74b (collectively referred to as side 74). However, in less preferred embodiments, the spoiler 7 may have open side surfaces or its front surface 70 may be fused to the rear surface 76. Surfaces 70, 72, 74, and 76 are connected together to form a three-dimensional structure.

[0063] In Figure 2, the bottom surface 72 and the rear surface 76 of spoiler 7a are joined at a right angle, and therefore the rear surface 76 is positioned vertically. The rear surface 76 is a flat surface.

[0064] In the embodiment shown in Figure 3, the rear surface 76 of the spoiler 7b is divided into a first rear surface 76a and a second rear surface 76b. Both the first rear surface 76a and the second rear surface 76b are planar. The first rear surface 76a is vertical and connects to the apex of the front surface 70. The second rear surface 76b connects to the bottom surface 72 and the lower apex of the first rear surface 76a. The bottom surface 72 is not as deep as the front surface 70, and therefore the second rear surface 76b is positioned at a certain angle to the horizontal. The angle between the second rear surface 76b and the horizontal plane is at most 15 degrees. At larger angles, the flow tends to separate from the spoiler 7b and not travel vertically.

[0065] As shown in the embodiment of Figure 4, the spoiler 7c does not include a bottom surface 72, and instead the rear surface 76 is directly bonded to the front surface 70 at the lower apex of the front surface 70. However, here the rear surface 76 has substantially horizontal components that perform the same role as the bottom surface 72, as will be described throughout this specification. The rear surface 76 of the spoiler 7c is curved in a concave shape. In other words, this curvature eliminates the right-angle interface between the rear surface 76 and the bottom surface 72 of the spoiler 7a of the prior art, as these are fused together into a single surface. The tangent vector of the curvature of the rear surface 76 is not greater than 15 degrees and is greater than or equal to 0 degrees at any point.

[0066] The initial tangent at the lowest point (front to rear) of the rear surface 76 of spoiler 7c should not exceed 20 degrees with respect to the flow direction 3. Similarly, the initial tangent at the highest point (top to bottom) of the rear surface 76 of spoiler 7c should not exceed 20 degrees. At the point where these two tangents intersect, the curvature is increased to provide a smooth fusion between the upper and lower parts of the rear surface 76.

[0067] In the embodiment shown in Figure 5, the rear surface 76 of the spoiler 7d is divided into a first rear surface 76a and a second rear surface 76b. The first rear surface 76a is vertical and is connected to the top apex of the front surface 70. The second rear surface 76b is concave in shape and is connected to the bottom surface 72 and the lower apex of the first rear surface 76a.

[0068] In the illustrated embodiment, the bottom surface 72 of the spoiler 7 is horizontal (i.e., it exhibits the smallest surface area with respect to the incoming flow (i.e., the arriving flow) coming from the flow direction 3, as it is parallel to the flow direction 3), but in other embodiments, the bottom surface 72 of the spoiler 7 is angled slightly with respect to the flow direction 3. Preferably, the bottom surface 72 is positioned at an angle of 10 to 20 degrees with respect to the flow direction 3 so that the gap between the bottom surface 72 of the spoiler 7 and the vehicle body expands in size toward the cavity 2. This tends to increase the mass flow between the bottom surface 72 of the spoiler 7 and the vehicle body.

[0069] The rear surface 76 may be provided with notches, protrusions, or raised portions.

[0070] It has a lead-free immediate rear surface 76 that guides the fluid flow (i.e., jet) and adds a vertical component to the fluid flow such that at the ends of its path the fluid flow is substantially perpendicular to the original flow direction 3. This helps to increase the height of the shear layer located above the opening of the cavity 2. Increasing the height of the shear layer helps to reduce / eliminate acoustic fatigue and provides a cavity flow more suitable for the installation of a supported payload (e.g., devices, equipment, instrumentation) within the cavity 2.

[0071] Consider the example of a car with a sunroof. A spoiler 7, as generally described above, may be located in front of the sunroof opening, but it may be raised above the car's body to allow fluid flow to travel through the gap directly beneath the spoiler 7. The shape of the rear surface 76 and (possibly) the bottom surface 72 of the spoiler 7 tends to maintain fluid flow attached to the bottom surface 72 of the spoiler 7. This will result in fluid flow traveling through the gap such that its trajectory changes from one parallel to the body surface (i.e., along the flow direction 3) to one with a trajectory having a velocity component normal to the incoming flow direction 3. In other words, fluid particles are carried by the bottom surface 72 and rear surface 76 of the spoiler 7 and directed upward onto the cavity 2 to a greater extent than otherwise.

[0072] The operation of the bay module 100 is described here with reference to Figures 6a-6b. Here, a combat aircraft 200 having the bay module 100 is illustrated, but it will be recognized that the bay module 100 can be installed in other forms of vehicles. The bay module 100 is shown in cross-section, and the rest of the aircraft 200 is shown in schematic form.

[0073] Figure 6a shows a closed bay module 100, where the sides of the bay module 100 having openings, i.e., apertures defined by the edges 14, 16, and 18 of the cavity 2, face the inside of the aircraft 200. The outer surface of the base 1 of the bay module 100 faces the ambient atmosphere outside the aircraft 200.

[0074] The bay module 100 is shown installed in the underside of the fuselage of the aircraft 200. The bay module 100 may instead be installed in the shoulder or wing of the fuselage of the aircraft 200.

[0075] The shaft 11 connects the bay module 100 to the motor 9 at the pivot point 6. The motor 9 is, for example, an electric motor. When activated, the motor 9 drives the shaft 11 to rotate, thereby opening or closing the bay module 100. In other embodiments, the motor 9 may be directly connected to the pivot point 6. Again in other embodiments, the bay 100 may have a motor 9 mechanically connected to a fixed point in the body of the aircraft 200. When in use, the bay module 100 may be configured to extend into the ambient flow or to retract into the aircraft 200 before rotating into an open configuration.

[0076] The bay module 100 can translate and rotate simultaneously. Alternatively, the bay module 100 may be configured to rotate about only one axis 4.

[0077] The outer edge of the base 1, when in a closed configuration, can form a relatively tight seal with the outer skin of the aircraft 200 surrounding the bay module 100. The base 1 may extend beyond the shape defined by the outer surfaces of the walls 8, 10, and 12 of the bay module 100. In other words, the outer surface of the base 1 may be conformal to the outer skin of the aircraft 200.

[0078] Figure 6b illustrates an open-configuration bay module 100, where motor 9 drives and rotates the bay module 100 so that the opening of the cavity 2 faces the ambient atmosphere and exposes the payload to the interior. The spoiler 7, which protrudes above the front surface of the front lip of the cavity 2, is therefore shown protruding into the ambient airflow.

[0079] Instead of being rotatable as described above, bay 100 may be fixed (i.e., static), permanently open, or equipped with a hinged door. Here, spoiler 7 may be configured to fold or slide into cavity 2 for storage, as described above.

[0080] The surrounding fluid through which Bay 100 passes is described above as airflow (i.e., air current), but it could be water instead. It will be understood that specific design features will depend on the cavity system and its operating environment, i.e., air, land, or sea.

[0081] Furthermore, in embodiments having the shape of the cavity 2 as described above, including an irregularly shaped cavity 2, those skilled in the art will recognize that the directions described above as parallel, transverse, perpendicular, etc., suitable for a regularly shaped cavity 2 can be modified to provide other directions that achieve the corresponding functions at least to some extent, as described above as parallel, transverse, perpendicular, etc. Also, even when the cavity 2 has a regularly shaped form, and in further embodiments, directions including decomposed parts of the described parallel, transverse, perpendicular, etc. directions can be implemented instead of completely parallel, transverse, perpendicular, etc. directions. For example, the spoiler 7 crosses in front of a rectangular cavity 2 at an oblique angle to a given direction, but may include decomposed elements of that direction, and therefore decomposed elements of its effect, in directions such as 15°, 30°, or 45° with respect to the direction parallel to the front edge 14.

[0082] The embodiments described above relate to a spoiler 7 suitable for use on aircraft such as civilian passenger aircraft, military jet fighters, or helicopters, but it will be recognized that the spoiler is also suitable for use on other forms of vehicles. The spoiler 7 is applicable to land vehicles such as trains and high-performance cars, as well as naval vessels such as yachts and submarines. The cavity 2 may be a wheel bay, a torpedo tube, a weapons bay, a window, a sunroof, an open superstructure, or any other cavity through which fluid passes or through.

[0083] A singular reference does not exclude the plural; therefore, references to "a," "an," "first," "second," etc., do not exclude the plural. In the claims, the terms "equip" or "include" do not exclude the presence of other elements.

[0084] Where the foregoing description refers to integers or elements having known, obvious, or predictable equivalents, such equivalents are incorporated herein as if they were individually described. References to the claims should be made to determine the true scope of the disclosure, and should be interpreted to encompass any such equivalents. It will also be recognized by the reader that integers or features of the disclosure described as optional do not limit the scope of the independent claims. Furthermore, it should be understood that such optional integers or features may be advantageous in some embodiments of the disclosure, but may be undesirable and therefore may not be present in other embodiments.

Claims

1. It is a vehicle, The exterior panels and, A cavity exposed to the outside atmosphere of the vehicle, A spoiler positioned close to the front edge of the aforementioned cavity The spoiler comprises, the front edge being relative to the actual or intended flow direction of the fluid over the cavity, The bottom surface, rear surface, and front surface, wherein, during use, the front surface faces the fluid coming from the direction of flow, and the bottom surface faces the outer plate. At least one support member for raising the spoiler is provided above the outer panel of the vehicle, such that a gap is provided between the outer panel and the lower surface of the spoiler, wherein the outer panel, lower surface and rear surface are arranged such that fluid passing through the gap is carried along and the height of the shear layer above the cavity. A vehicle equipped with [a certain feature].

2. The vehicle according to claim 1, wherein the support member comprises a hinge for causing the spoiler to rotate relative to the vehicle.

3. The vehicle according to claim 1, wherein the support member is provided with a sliding mechanism for raising the spoiler so that it moves away from the outer panel.

4. The vehicle according to claim 2 or 3, wherein the support member is coupled to the inner surface of the cavity.

5. The vehicle according to any one of claims 1 to 4, comprising a secondary cavity located in front of the aforementioned cavity, wherein the spoiler is arranged to retract into the secondary cavity when not in a deployed configuration.

6. The vehicle according to any one of claims 1 to 5, wherein the rear surface comprises a curved portion.

7. The vehicle according to claim 6, wherein the rear surface comprises a vertical portion and a curved portion.

8. The vehicle according to claim 6 or 7, wherein the curved portion has a concave curve with respect to the actual or intended flow direction.

9. The vehicle according to any one of claims 6 to 8, wherein the tangent to the angle of curvature at any point along the curved portion is greater than 0 degrees and less than or equal to 15 degrees.

10. The vehicle according to any one of claims 6 to 9, wherein the rear surface and the lower surface are components of a single surface.

11. The vehicle according to any one of claims 1 to 5, wherein the rear surface comprises a planar portion angled acutely with respect to a horizontal plane.

12. The vehicle according to claim 11, wherein the angle of the rear surface with respect to the horizontal is greater than 0 degrees and 15 degrees or less.

13. The vehicle according to any one of claims 1 to 12, wherein the outer panel, from which the spoiler is raised above it, is angled with respect to a horizontal plane such that its height increases in the direction of the flow.

14. The vehicle according to claim 13, wherein the outer panel on which the spoiler is raised above is curved to form an inclination with respect to the incoming flow.

15. The vehicle according to any one of claims 1 to 14, wherein the cavity is a payload bay for storing a payload.

16. The vehicle according to claim 15, wherein the cavity is a rotatable payload bay configured to rotate so as to expose the payload to the surrounding atmosphere.

17. The vehicle according to any one of claims 1 to 16, wherein the vehicle is an aircraft and the fluid is air.

18. The vehicle according to any one of claims 1 to 17, wherein the vehicle is a car and the fluid is air.

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