101 results about "Angle of attack" patented technology

The application discloses a high angle of attack nonlinear separated flow aerodynamic force correction method, which comprises the following steps: obtaining aircraft surface pressure distribution data at zero reduced frequency by using a DES method; dividing surface elements on the surface area of the aircraft, and generating an AIC matrix AIC by using a dipole grid method based on the geometric information of each surface element; obtaining the aerodynamic force and moment of each surface element according to the AIC, and generating an aerodynamic force matrix A DLM,k＝0 of all surface elements at zero reduced frequency by using the aerodynamic force and moment of each surface element; interpolating the aircraft surface pressure distribution data obtained by using the DES method to each surface element to obtain the aerodynamic force matrix A DES of all surface elements; obtaining a force correction matrix W according to A DLM,k＝0 and A DES ; correcting the AIC matrix AIC by using the force correction matrix W to obtain a corrected aerodynamic force influence coefficient matrix AIC * ; and performing aerodynamic force correction and aeroelastic calculation by using the corrected aerodynamic force influence coefficient matrix AIC * , so as to complete the high angle of attack nonlinear separated flow aerodynamic force correction. The application can have both the calculation precision of CFD and the calculation efficiency of an engineering method.

The application discloses a solid binding rocket booster landing point calculation method, which comprises the following steps: establishing a six-degree-of-freedom dynamics model of a solid booster; the six-degree-of-freedom dynamics model is a function of passive section state variables about the total moment on the rocket system; establishing an angle of attack model and an angle of incidence model; obtaining the total moment on the rocket system in the falling process of the booster according to the angle of attack model and the angle of incidence model; taking the data of the booster separation point as the simulation initial value, substituting the total moment on the rocket system into the six-degree-of-freedom dynamics model for simulation, and obtaining the booster landing point information. The application can quickly analyze the trajectory characteristic parameters of the solid booster in the falling section, find the passive section motion law, and make the solid booster landing point calculation result more accurate.

The application provides a kayak athlete power output coordination control method, comprising: collecting the paddle water entry depth, the angle of attack deflection angle, the athlete power time and the hull acceleration, obtaining the complete record containing the paddle track arc and the hull acceleration change; according to the change of the straight line track and the arc track when the hull accelerates, the angle of attack deflection angle is extracted, the deviation degree of the angle of attack deflection angle and the effective propulsion angle range is evaluated, and the proportion of energy loss caused by the lateral component force under different deviation degrees is identified; according to the power output timing coordination score, the smoothness of the power transmission among the athlete, the paddle and the hull is analyzed, and the stability of the transmission efficiency in the acceleration stage is identified after removing the interference signal; according to the track optimization direction adjustment training system collection setting, the track optimization direction is returned to the collection density adjustment link, and the time interval setting of the next data collection is determined.

A system and method for controlling a VTOL aircraft to minimize acoustic noise. In a hover mode, the aircraft may be controlled to utilize a blade pitch angle and corresponding angle of attack range which minimizes variations in the boundary layer separation location to a point or narrow region, which reduces noise generation. The propeller blades used in the system are configured to have a reduced or no shift of the point of flow separation on the airfoil as a function of angle of attack during the hover mode. The blade design may trade off overall blade efficiency in exchange for the reduced noise during hover.

A rotor (17, 17') is described, comprising a motor element (16) having an output shaft (18) rotatable about a first axis (C) and controllable by acceleration (a); a rotor hub (19, 19') connected to the output shaft (18); two blades (25) rotatable about the first axis (C); two connecting members (21, 21') connected to the blades (25) and operable for adjusting the angle of attack (α, β, γ; α, β) of the blades (25); a control element (20, 20') connected to the connecting members (21) and rotatable about the first axis (C); and a rotor hub (19, 17') adapted to constrain the rotor hub (17, 17'). The constraint device (23) of the control element (20, 20') and the control element (20, 20'); when the absolute value of acceleration (a) is less than / greater than a threshold (Ta), the constraint device (23, 23') keeps the control element and the hub (20, 19; 20', 19') angularly integrated about a first axis (C) and in a first / second relative position relative to each other, such that the angle of attack (α, β, γ; α, β) takes a first value; when the absolute value of acceleration (a) reaches the threshold (Ta), the constraint device (23, 23') allows relative rotation between the control element and the hub (20, 19; 20', 19') between the first and second positions.

An aircraft capable of transonic flight is equipped with a slotted airfoil to significantly improve the cruise performance during flight. The aircraft includes a plurality of slotted airfoils uniquely configured to maximize natural laminar flow across the aircraft wings. In addition to reduced wing drag, the unique configuration minimizes shocks at various conditions over the course of a flight. Each slotted airfoil includes a fore element, an after element, and a slot disposed between the fore element and aft element. The aft element is maneuverable relative to the fore element. The slot is configured to promote a substantially constant air flow field onto the aft element during all flight angles of attack.

This invention provides a displacement-type eddy current generator and its position control method, belonging to the field of active flow control equipment. The eddy current generator (VG) includes a belt, belt guide rail, belt bearing, slider, support column, triangular VG body, guide rail support block, limiting groove, body connecting plate, and motor. The belt is mounted on the belt guide rail and driven by the motor. The slider, which is concave in shape and mounted on the belt, is connected to the body connecting plate via the support column. The VG body is fixed at both ends of the body connecting plate. The belt guide rail is mounted on the guide rail support block, allowing the slider to move within the limiting groove. By controlling the motor to drive the belt, the slider and VG body move, achieving precise adjustment of the eddy current generator's position. This invention automatically adjusts the eddy current generator position according to changes in incoming wind speed and angle of attack, maintaining optimal aerodynamic performance under different operating conditions, significantly improving the aerodynamic performance and power generation efficiency of wind turbine blades, and effectively mitigating the negative impact of leading-edge roughness.

The present application relates to a kind of static pressure correction method and the drag cone system used by it, by being arranged at the position where the influence of drag cone tube static pressure hole is less, inclination sensor can obtain the angle of attack of drag cone tube in flight calibration process, improve the precision of drag cone calibration.The beneficial effects of the present application are that traditional drag cone method has the advantages of wide airspeed range and simple supporting facilities.In addition, it can further eliminate the static pressure measurement error caused by the angle of attack of drag cone tube, and after correction, it can improve the accuracy of reference static pressure measurement, and the installed inclination sensor can not cause significant adverse effects on static pressure measurement.

The invention relates to a method for the aerodynamically optimized adjustment of a rear spoiler (3) of a vehicle (1), whereby the position of the rear spoiler (3) relative to the vehicle (1) is changed to minimize turbulence occurring in a wake zone (33) of the airflow at the rear of the vehicle. In this method, which further improves the aerodynamics in the rear of the vehicle, the air density in the wake zone (33) is determined based on current vehicle and / or vehicle environment conditions during the vehicle's (1) operation, and, depending on the determined air density, the angle of attack (μ) of the rear spoiler (3) is adaptively adjusted to minimize turbulence occurring in the wake zone (33) at the rear.

The application discloses a method for mapping aerodynamic force of aerodynamic elasticity of a heavy gas wind tunnel to air medium, and belongs to the technical field of high-speed wind tunnel test. The application determines key influence parameters of aerodynamic force characteristics in the heavy gas medium through dimensional analysis, derives flow similarity parameters of the heavy gas and the air medium through similarity analysis, determines the equivalent Mach number of the heavy gas medium according to the similarity condition, and finally accurately maps the aerodynamic force coefficients related to aerodynamic elasticity measured in the heavy gas medium to the air medium through mapping parameters, so that the equivalent conversion of the aerodynamic force of the aerodynamic elasticity test of the heavy gas medium wind tunnel to the air medium is realized, and then the equivalent conversion of the flutter characteristics is realized through the aerodynamic force mapping relationship. The application solves the technical problem that the aerodynamic test results cannot be directly applied due to the difference in thermodynamic characteristics between the heavy gas and the air medium, the slope error of the aerodynamic force coefficient in the small attack angle range after mapping is not more than 2%, and the application can be used for perfecting the application system of the heavy gas wind tunnel test data.

The invention relates to a device for the roll-stabilization of a watercraft in motion, at anchor, or at zero speed, and / or for influencing the course of the watercraft, including a fin-carrying shaft on which a guide fin is disposed, wherein for changing an actual angle of attack of the guide fin in the water, the fin-carrying shaft is drivable by an electromechanical drive unit, and the drive unit is disposed on the hull using a base. According to the invention it is provided that the electromechanical drive unit is configured with a synchronous motor that drives the fin-carrying shaft using a reducing eccentric transmission. The device thereby has a significantly reduced installation space requirement, causes only slight operating noises, and is also optimally electronically regulable.

The apparatus (100) for harvesting energy from water waves comprises a float arrangement (110) for floating the apparatus and altering an angle of attack of the apparatus (100) in response to water waves. Further the float arrangement forms a pivot point (111) of the apparatus around which the apparatus turns. The apparatus further comprises a hull (120) at the float arrangement (110) for accommodating at least a fluid (140). The hull (120) comprises an elongated path (122). At least a portion of the elongated path (122) is positioned at a distance from the pivot point (111) of the apparatus. The hull (120) further comprises a mounting portion (124) for receiving a turbine (150). The mounting portion (124) is arranged to the portion of the elongated path (122) locating at a distance from the pivot point (111) of apparatus (100). The arrangement further comprises a fluid (140) at least partially fulfilling the elongated path (122) of the hull (110). The arrangement further comprises a turbine (150) mounted to the mounting portion (124) of the hull (110), wherein the turbine (150) is configured to move relative to the fluid (140) and spin as the angle of attack of the apparatus (100) alters.

This utility model discloses a blade, a propeller, and an aircraft, belonging to the field of aircraft technology. The blade includes a connected root and a shaft. The root has a root centerline, and the distance from the end of the blade furthest from the root to the root centerline is a first length. At the first position of the blade, the angle of attack is 18.38°±2.5°; at the second position, the angle of attack is 9.58°±2.5°; and at the third position, the angle of attack is 6.61°±2.5°. The distance from the first position of the blade to the root centerline is 20% to 25% of the first length; the distance from the second position of the blade to the root centerline is 50% to 58% of the first length; and the distance from the third position of the blade to the root centerline is 80% to 95% of the first length. The blade of this utility model, through the design of the angle of attack at multiple key positions of the main body of the propeller shaft, reduces air resistance and improves aerodynamic efficiency. The propeller and aircraft of this invention improve the aerodynamic efficiency of the propeller and the flight efficiency of the aircraft.

The embodiment of the application relates to the technical field of flight control, and discloses a wide-range aircraft attitude control method, device and equipment, which comprises the following steps: constructing a dynamic model of a wide-range aircraft based on a nonlinear model state quantity and a control input; obtaining a linear variable parameter model of the wide-range aircraft based on the dynamic model of the wide-range aircraft by adopting a linear variable parameter vector, the linear variable parameter vector comprising a Mach number, a flight height, an angle of attack and a sideslip angle; constructing a self-disturbance rejection controller of a roll channel, a pitch channel and a yaw channel based on the linear variable parameter model of the wide-range aircraft for flight attitude control; and performing attitude control on a target wide-range aircraft according to the self-disturbance rejection controller of the roll channel, the pitch channel and the yaw channel. The self-disturbance rejection controller is used for responding to local uncertainty in a mode, so that high-precision stable control of the wide-range aircraft is realized.

This invention discloses an intelligent adjustable multi-hydrofoil high-speed planing boat suitable for both new ship manufacturing and old ship retrofitting, belonging to the field of high-speed vessel technology. The invention includes a hull, three hydrofoil assemblies, and a stern propulsion mechanism. All three hydrofoil assemblies are equipped with a rack and pinion electric lifting mechanism, allowing manual setting and fixing of the overall hydrofoil height to adapt to different navigation draft requirements. Only the bow hydrofoil is hinged and equipped with an AI intelligent real-time control system, which can dynamically adjust the hydrofoil's tilt angle of attack during navigation, adaptively optimizing the hull's planing attitude and improving stability. The stern propulsion mechanism is equipped with a hydraulic lifting device, allowing for overall elevation adjustment of the water depth, achieving shallow-water grounding prevention and high-efficiency deep-water navigation. This invention is applicable to both the overall manufacturing of new ships and the retrofitting and upgrading of existing conventional planing boats. Its novel structural design distinguishes between two adjustment modes: fixed hydrofoil height adjustment and AI real-time intelligent angle adjustment. Combined with the hydraulically adjustable propulsion structure, it significantly improves the planing boat's intelligence, navigation stability, and water adaptability, demonstrating promising application prospects.

The application provides a stall flight test method for a fly-by-wire civil aircraft based on a high angle-of-attack protection function, which comprises the following steps: step 1, completing preparation work before flight test; step 2, performing stall characteristic flight test verification under an auxiliary control law, and preliminarily confirming a protection angle of attack and a maximum angle of attack of the high angle-of-attack protection of the fly-by-wire civil aircraft; step 3, performing stall characteristic flight test verification under a normal control law, and determining an angle-of-attack working range of the high angle-of-attack protection by loading the protection angle of attack and the maximum angle of attack of the high angle-of-attack protection determined in step 2; step 4, performing stall characteristic flight test verification on the fly-by-wire civil aircraft under various scenes; and step 5, performing stall characteristic flight test verification under an angle-of-attack overshoot state. The technical scheme of the embodiment of the application can ensure that the stall envelope of the aircraft can be safely and effectively tested under high vibration characteristics through reasonable task planning, flight test action criteria and data processing.

This application relates to the field of simulation and calculation technology, and in particular to a nonlinear galloping simulation, risk assessment method and medium for ice-wind composite contact networks. By introducing an unsteady aerodynamic correction term related to the rate of change of angle of attack and a geometric stiffness matrix updated in real time with tension, this application successfully constructs an unsteady aerodynamic negative damping mechanism, which can simulate the negative aerodynamic damping effect that traditional linear methods cannot capture. This significantly improves the prediction accuracy of the galloping start-up wind speed and the maximum amplitude, and solves the technical problem that traditional quasi-steady linear models cannot accurately predict the large-amplitude galloping characteristics of ice-covered contact networks. It realizes accurate simulation and assessment of start-up wind speed, galloping amplitude and risk level, and is suitable for the analysis of the survivability of contact networks under extreme ice-wind conditions.

This invention provides a method for automatically leveling and attitude measurement of a three-degree-of-freedom support system in a low-speed wind tunnel. The method includes: installing a dual-axis accelerometer on the support system's strut, such that its first sensitive axis is parallel to the pitch axis of the aircraft model and its second sensitive axis is parallel to the roll axis of the model; controlling the roll motor and angle-of-attack motor of the support system so that the output values ​​of both the first and second sensitive axes are zero, thus achieving automatic leveling of the model; during wind tunnel testing, comparing the roll angle measured by a first encoder (detecting the roll angle) and the angle of attack measured by a second encoder (detecting the angle of attack), using a first threshold and a second threshold, selecting the roll angle detected by the first sensitive axis or the measurement value of the first encoder as the actual roll angle of the model, and selecting the angle of attack detected by the second sensitive axis or the measurement value of the second encoder as the actual angle of attack of the model, thereby improving the measurement accuracy of the aircraft model's attitude angle during wind tunnel dynamic testing.

This invention provides a method and system for optimizing nozzle layout and jet reaction control, comprising: Step 1: Nozzle layout design: adjusting the nozzle from the side of the aircraft to the top surface; Step 2: Numerical simulation verification: analyzing the interference effects under different nozzle layouts using CFD numerical simulation methods and verifying the optimized control effect; Step 3: Experimental verification: verifying the control effect of the optimized nozzle layout under different altitudes and angles of attack conditions through wind tunnel experiments or actual flight tests; Step 4: Control system integration: integrating the optimized nozzle layout into the jet reaction control system of the aircraft, and optimizing the jet opening time and intensity through control algorithms to improve control accuracy and efficiency. This invention can improve jet control capability by rationally designing the nozzle position and utilizing the interference effect between the jet and the aircraft structure.

This invention discloses an adaptive turbulence simulation method suitable for calculating the flow separation of underwater vehicles, the steps of which are as follows: k‑e The turbulence model stress is remodeled, and the subgrid-scale turbulence stress tensor is obtained through Reynolds stress attenuation. The resolution control function is improved based on the turbulence energy spectrum. The filtering scale coefficients in the resolution control function are calculated, and the magnitude of the resolution control function is further calculated. An adaptive transition between unsteady RANS, LES, and DNS turbulence models is achieved. The adaptive turbulence simulation modeling process is completed. Unsteady calculations are performed on the flow around underwater vehicles. The method of this invention can accurately simulate and predict the flow around underwater vehicles at large angles of attack and flow separation phenomena under relatively coarse computational grids.

This invention relates to the technical field of wind power generation, and proposes an adaptive wind speed wind power generation method, system, and device. The method includes the following steps: acquiring radial distance data and wind speed data of each adjustable segment blade of the wind turbine; calculating the target angle of attack of each adjustable segment blade; calculating the deviation between the target angle of attack and the current angle of attack of each adjustable segment blade, converting it into the rotation angle of the actuator motor, and sending it to the corresponding actuator motor of each adjustable segment blade; controlling each actuator motor to rotate according to the rotation angle, thereby driving the corresponding adjustable segment blade to rotate. This invention automatically matches a larger angle of attack according to the wind force, effectively reducing fatigue damage while ensuring lift and power generation efficiency. When the wind speed is too high, a safe angle of attack can be used to reduce the risk of sudden changes in local load, aerodynamic stall, and extreme loads, thereby effectively improving safety and extending service life.

This application relates to the field of airfoil design technology, specifically to a stepped airfoil and its design method. A recessed step with a smooth curved surface is provided in the middle of the lower surface of the airfoil. Along the leading and trailing edges of the stepped airfoil, the center point P of the recessed step is located between 0.25C and 0.8C, the depth D of the recessed step ranges from 0.005C to 0.02C, and the aspect ratio L / W of the recessed step is (2:1) to (4:1), where C is the chord length of the stepped airfoil, L is the length of the recessed step, and W is the width of the recessed step, with W ranging from 0.02C to 0.05C. This stepped airfoil can achieve a lift-to-drag ratio improvement of over 15% at the design angle of attack and exhibits good performance gains within the design angle of attack range. The design method, combining the Hua Luogeng optimization method and the coordinate rotation method, can achieve multi-parameter optimization without calculating gradients, effectively solving multi-parameter airfoil optimization problems with fast convergence speed and high computational efficiency.

The present disclosure relates to a robust design optimization method of compressor blade profile under multiple working conditions considering Mach number and a blade, the method comprising: establishing a design sample space by taking design parameters of the blade profile and incoming flow working condition parameters as variables; selecting multiple design sample points in the design sample space, each of which comprises the design parameters and the incoming flow working condition parameters; generating the blade profile corresponding to each design sample point according to the design parameters of the design sample point and a blade profile generation method; performing numerical calculation on the blade profile according to the incoming flow working condition parameters to obtain loss coefficients of the blade profile under different incoming flow attack angles; constructing a weight function and an objective function of the blade profile according to the loss coefficients and the incoming flow working condition parameters; establishing an approximate surrogate model according to the design parameters and the corresponding objective function values of each blade profile, and performing optimization calculation by using an optimization algorithm to obtain an optimal blade profile; the incoming flow working condition parameters comprise an incoming flow attack angle and a Mach number of the blade.

This utility model discloses a blade, a propeller, and a drone, belonging to the field of aircraft technology. The blade includes a connected root and a blade body. The root has a root centerline, and the distance from the end of the blade furthest from the root to the root centerline is a first length. The blade angle of attack is designed at multiple positions at a distance of the first length from the root centerline. This utility model reduces air resistance and improves aerodynamic efficiency by designing the angle of attack at multiple key positions of the blade. The blade profile is optimized, resulting in lower torque within a higher speed range, thereby reducing the motor's output power and increasing the drone's endurance. The aerodynamic efficiency of the propeller is improved, thus enhancing the drone's flight efficiency.

This invention discloses a method for predicting the high-Mach aerodynamic characteristics of a Mars orbiter based on FLUENT, belonging to the aerospace field. This invention establishes a symmetrical geometric model of the Mars orbiter and uses a dual-temperature model based on FLUENT to achieve numerical simulation of the Mars orbiter under high-Mach conditions in CO2 medium. By setting a boundary layer based on O-Block mesh coupling, it achieves unified simulation prediction for different velocities and angles of attack, reducing the computational burden of re-partitioning the mesh for different conditions, thereby improving the efficiency of aerodynamic characteristic prediction. Simultaneously, it can accurately simulate and analyze the aerodynamic characteristics of the Mars orbiter under different conditions, enabling the corresponding aerodynamic performance evaluation of the Mars orbiter. This invention can analyze and construct the hypersonic aerodynamic characteristics of the Mars orbiter under different high-Mach conditions upon entering the Martian atmosphere, assisting in the optimization of the Mars orbiter and guidance and control commands.

The application relates to a control method of a hydrofoil craft rudder engine, which is operated on an embedded control system and is used for realizing the pitching and heaving motion control of a hydrofoil craft by controlling a hydrofoil rudder engine, and the method comprises the following steps: S1: acquiring the current motion state of the hydrofoil craft through a sensor and receiving a desired heaving height instruction and a desired pitching angle instruction; S2: inputting the desired heaving height instruction and the desired pitching angle instruction into a nonlinear feedforward controller based on a simplified model of hydrofoil dynamics, wherein the feedforward controller calculates a basic attack angle instruction of the hydrofoil rudder engine by solving an inverse dynamics problem containing the nonlinear lift characteristics of the hydrofoil; and S3: comparing the current motion state with the desired instruction to generate a heaving height error and a pitching angle error; the application can precisely control the pitching and heaving against disturbance, and improves the control effect of the hydrofoil craft.

This invention discloses a tilt-lift short takeoff and landing (STOVL) aircraft and its control method, comprising a fuselage, wing assembly, multi-layered distributed propulsion system, tilt drive assembly, and control unit. The wing is hinged to the fuselage via a pivot in the mid-rear section of the chord, and the tilt drive assembly drives the wing to rotate and adjust the angle of attack. The multi-layered distributed propulsion system includes a first rotor assembly located in the mid-rear section to the wingtip region of the wing and a second rotor assembly located on the lower surface of the wing near the fuselage. During cruise, the first rotor assembly is stopped and feathered, and the propulsion system tilts synchronously with the wing. This invention, through a layered distributed propulsion layout and synchronous wing tilting for synergistic lift enhancement, solves the problems of insufficient control torque at low speeds and high cruise energy consumption, achieving a balance between STOVL performance and cruise economy.