The Experts below are selected from a list of 18021 Experts worldwide ranked by ideXlab platform
Fei Xue - One of the best experts on this subject based on the ideXlab platform.
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derivation and validation of wind tunnel free flight Similarity Law for store separation from aircraft
Aerospace Science and Technology, 2020Co-Authors: Fei Xue, Yuchao Wang, Han QinAbstract:Abstract This paper describes a design method for a Similarity Law for free-flight tests of aircraft load separation. The effect of the initial separation velocity on the motion Similarity is considered. For the first time, the initial separation velocity is introduced into the equation of motion to identify similar trajectories. Finally, the model mass parameter characteristics and separation velocity equation are solved to determine Similarity Laws for wind tunnel tests, greatly improving the accuracy and applicability of test results from wind tunnels. The proposed derivation overcomes the problems faced by the traditional light model method and the traditional heavy model method, namely that they are limited in terms of ejection separation and cannot be realized in wind tunnel tests. The typical separation state under wind load scenarios is simulated using computational fluid dynamics (CFD). Separation data from real aircraft and previous test methods are compared with the simulation data obtained by the new Similarity Law design method. The improvement of the new Similarity Law in terms of trajectory simulation is verified through a comprehensive data comparison. The data show that the new Similarity Law greatly improves the accuracy of wind tunnel tests.
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optimization and verification of free flight separation Similarity Law in high speed wind tunnel
Chinese Journal of Aeronautics, 2020Co-Authors: Fei Xue, Zenghui Jiang, Yuchao Wang, Xin Jin, Peihua Feng, Han Qin, Peng BaiAbstract:Abstract Based on the Similarity of separation time, a Similarity Law optimization method for high-speed weapon delivery test is derived. The typical separation state under wind load is simulated by the numerical method. The real separation data of aircraft, separation data of previous test methods, separation data of ideal wind tunnel test of previous methods, and simulation data of the proposed optimization method are obtained. A comparison of the data shows that the method proposed can improve the performance of tracking. Similarity Law optimization starts with the development of motion equations and dynamic equations in the windless state to address the problems of mismatching between vertical and horizontal displacement, and to address the problems of separation trajectory distortion caused by insufficient gravity acceleration of the scaling model of existing light model. The ejection velocity of the model is taken as a factor/vector, and is adjusted reasonably to compensate the linear displacement insufficiency caused by the insufficient vertical acceleration of the light model method, so as to ensure the matching of the vertical and horizontal displacement of the projectile, and to improve the consistency between the test results of high-speed projection and the actual separation trajectory. The optimized Similarity Law is applicable to many existing free-throwing modes of high-speed wind tunnels. The optimized Similarity Law is not affected by the ejection velocity and hanging mode of the projectile. The optimized Similarity Law is suitable not only for the launching of the buried ammunition compartment and external stores, but also for the test design of projectile launching and gravity separation.
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Derivation and verification of a Similarity Law for wind-tunnel free-flight tests of heavy-store separation
Acta Astronautica, 2020Co-Authors: Fei Xue, Huaqiang Wang, Zenghui Jiang, Yuchao WangAbstract:Abstract Test-method research was carried out to consider the separation of a heavy store, and a Similarity Law for unsteady wind-tunnel free-flight tests of air-launch rockets was derived. The derivation of this Similarity Law considers the particular characteristics of a heavy store and aerodynamic interference with the carrier and focuses on solving the following problems: the separation of a heavy store causes a real carrier to have an acceleration and a velocity that cannot be ignored; the carrier in a wind-tunnel test is vertically fixed; and a wind-tunnel test cannot meet the Froude number (Fr) Similarity condition. According to the special characteristics of heavy-store separation, a Similarity Law for wind-tunnel free-flight tests of heavy-store separation is derived. Computational fluid dynamics simulations are used to verify the new Similarity Law. The results show that the new Similarity Law can simulate the separation trajectory more realistically than existing methods, and the linear and angular displacement errors are decreased by an order of magnitude. The experimental accuracy of the new Similarity Law is even higher than that of a separation trajectory satisfying Fr matching. It is demonstrated that the new Similarity Law can be used to carry out unsteady experimental research on the separation of a heavy store such as an air-launch rocket, and this new Law provides strong support for establishing the safety boundaries of heavy-store separation.
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free flight wind tunnel test Similarity Law derivation for light store separation from aircraft
Advances in Mechanical Engineering, 2019Co-Authors: Fei Xue, Zenghui Jiang, Yuchao Wang, Xin Jin, Han Qin, Peng BaiAbstract:Based on the linear displacement motion Similarity and angular displacement motion Similarity, the Similarity Law for free flight test of light store separation from aircraft is deduced. The proble...
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Optimization and verification of wind tunnel free-flight Similarity Law for separation of cluster munition
Chinese Journal of Aeronautics, 1Co-Authors: Fei Xue, Huaqiang Wang, Zenghui Jiang, Yuchao Wang, Han Qin, Jun Tang, Peng BaiAbstract:Abstract In view of the separation form of the separator from the back of the carrier upward and from the side of the carrier outward, separation-safety research is carried out by taking the separation of a cluster munition as an example. In previous wind tunnel free-flight tests, the Similarity Law of vertical, downward, moving submunition was used to design submunitions at different positions in different initial-velocity directions, which resulted in large discrepancies between wind tunnel test results and real flight. In a wind tunnel test, each submunition has an independent time-reduction ratio with respect to the dispenser. Even if the separation trajectory of a single submunition is accurate, there will be errors in the position of each submunition at a given time. Therefore, it is necessary to determine the time-reduction ratio between submunitions, and to modify the test results later. In order to ensure the accuracy of wind tunnel test results, the Similarity Law of a free-flight test in a wind tunnel is derived in this paper. The time-correction scheme to ensure motion Similarity between submunitions is solved. Numerical simulation is used to simulate the separation of a wind tunnel test and real aircraft, and the motion parameters of different submunitions are solved. The results show that the new Similarity Laws derived for different types of submunitions can greatly reduce the errors caused by previous Similarity Laws. In addition to the case for the separation of a cluster munition, the Similarity Law can also be applied to the free-flight test design of wind tunnels for vertical separation and horizontal separation of other kinds of aircraft.
Yuchao Wang - One of the best experts on this subject based on the ideXlab platform.
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derivation and validation of wind tunnel free flight Similarity Law for store separation from aircraft
Aerospace Science and Technology, 2020Co-Authors: Fei Xue, Yuchao Wang, Han QinAbstract:Abstract This paper describes a design method for a Similarity Law for free-flight tests of aircraft load separation. The effect of the initial separation velocity on the motion Similarity is considered. For the first time, the initial separation velocity is introduced into the equation of motion to identify similar trajectories. Finally, the model mass parameter characteristics and separation velocity equation are solved to determine Similarity Laws for wind tunnel tests, greatly improving the accuracy and applicability of test results from wind tunnels. The proposed derivation overcomes the problems faced by the traditional light model method and the traditional heavy model method, namely that they are limited in terms of ejection separation and cannot be realized in wind tunnel tests. The typical separation state under wind load scenarios is simulated using computational fluid dynamics (CFD). Separation data from real aircraft and previous test methods are compared with the simulation data obtained by the new Similarity Law design method. The improvement of the new Similarity Law in terms of trajectory simulation is verified through a comprehensive data comparison. The data show that the new Similarity Law greatly improves the accuracy of wind tunnel tests.
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optimization and verification of free flight separation Similarity Law in high speed wind tunnel
Chinese Journal of Aeronautics, 2020Co-Authors: Fei Xue, Zenghui Jiang, Yuchao Wang, Xin Jin, Peihua Feng, Han Qin, Peng BaiAbstract:Abstract Based on the Similarity of separation time, a Similarity Law optimization method for high-speed weapon delivery test is derived. The typical separation state under wind load is simulated by the numerical method. The real separation data of aircraft, separation data of previous test methods, separation data of ideal wind tunnel test of previous methods, and simulation data of the proposed optimization method are obtained. A comparison of the data shows that the method proposed can improve the performance of tracking. Similarity Law optimization starts with the development of motion equations and dynamic equations in the windless state to address the problems of mismatching between vertical and horizontal displacement, and to address the problems of separation trajectory distortion caused by insufficient gravity acceleration of the scaling model of existing light model. The ejection velocity of the model is taken as a factor/vector, and is adjusted reasonably to compensate the linear displacement insufficiency caused by the insufficient vertical acceleration of the light model method, so as to ensure the matching of the vertical and horizontal displacement of the projectile, and to improve the consistency between the test results of high-speed projection and the actual separation trajectory. The optimized Similarity Law is applicable to many existing free-throwing modes of high-speed wind tunnels. The optimized Similarity Law is not affected by the ejection velocity and hanging mode of the projectile. The optimized Similarity Law is suitable not only for the launching of the buried ammunition compartment and external stores, but also for the test design of projectile launching and gravity separation.
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Derivation and verification of a Similarity Law for wind-tunnel free-flight tests of heavy-store separation
Acta Astronautica, 2020Co-Authors: Fei Xue, Huaqiang Wang, Zenghui Jiang, Yuchao WangAbstract:Abstract Test-method research was carried out to consider the separation of a heavy store, and a Similarity Law for unsteady wind-tunnel free-flight tests of air-launch rockets was derived. The derivation of this Similarity Law considers the particular characteristics of a heavy store and aerodynamic interference with the carrier and focuses on solving the following problems: the separation of a heavy store causes a real carrier to have an acceleration and a velocity that cannot be ignored; the carrier in a wind-tunnel test is vertically fixed; and a wind-tunnel test cannot meet the Froude number (Fr) Similarity condition. According to the special characteristics of heavy-store separation, a Similarity Law for wind-tunnel free-flight tests of heavy-store separation is derived. Computational fluid dynamics simulations are used to verify the new Similarity Law. The results show that the new Similarity Law can simulate the separation trajectory more realistically than existing methods, and the linear and angular displacement errors are decreased by an order of magnitude. The experimental accuracy of the new Similarity Law is even higher than that of a separation trajectory satisfying Fr matching. It is demonstrated that the new Similarity Law can be used to carry out unsteady experimental research on the separation of a heavy store such as an air-launch rocket, and this new Law provides strong support for establishing the safety boundaries of heavy-store separation.
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free flight wind tunnel test Similarity Law derivation for light store separation from aircraft
Advances in Mechanical Engineering, 2019Co-Authors: Fei Xue, Zenghui Jiang, Yuchao Wang, Xin Jin, Han Qin, Peng BaiAbstract:Based on the linear displacement motion Similarity and angular displacement motion Similarity, the Similarity Law for free flight test of light store separation from aircraft is deduced. The proble...
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Optimization and verification of wind tunnel free-flight Similarity Law for separation of cluster munition
Chinese Journal of Aeronautics, 1Co-Authors: Fei Xue, Huaqiang Wang, Zenghui Jiang, Yuchao Wang, Han Qin, Jun Tang, Peng BaiAbstract:Abstract In view of the separation form of the separator from the back of the carrier upward and from the side of the carrier outward, separation-safety research is carried out by taking the separation of a cluster munition as an example. In previous wind tunnel free-flight tests, the Similarity Law of vertical, downward, moving submunition was used to design submunitions at different positions in different initial-velocity directions, which resulted in large discrepancies between wind tunnel test results and real flight. In a wind tunnel test, each submunition has an independent time-reduction ratio with respect to the dispenser. Even if the separation trajectory of a single submunition is accurate, there will be errors in the position of each submunition at a given time. Therefore, it is necessary to determine the time-reduction ratio between submunitions, and to modify the test results later. In order to ensure the accuracy of wind tunnel test results, the Similarity Law of a free-flight test in a wind tunnel is derived in this paper. The time-correction scheme to ensure motion Similarity between submunitions is solved. Numerical simulation is used to simulate the separation of a wind tunnel test and real aircraft, and the motion parameters of different submunitions are solved. The results show that the new Similarity Laws derived for different types of submunitions can greatly reduce the errors caused by previous Similarity Laws. In addition to the case for the separation of a cluster munition, the Similarity Law can also be applied to the free-flight test design of wind tunnels for vertical separation and horizontal separation of other kinds of aircraft.
Peng Bai - One of the best experts on this subject based on the ideXlab platform.
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optimization and verification of free flight separation Similarity Law in high speed wind tunnel
Chinese Journal of Aeronautics, 2020Co-Authors: Fei Xue, Zenghui Jiang, Yuchao Wang, Xin Jin, Peihua Feng, Han Qin, Peng BaiAbstract:Abstract Based on the Similarity of separation time, a Similarity Law optimization method for high-speed weapon delivery test is derived. The typical separation state under wind load is simulated by the numerical method. The real separation data of aircraft, separation data of previous test methods, separation data of ideal wind tunnel test of previous methods, and simulation data of the proposed optimization method are obtained. A comparison of the data shows that the method proposed can improve the performance of tracking. Similarity Law optimization starts with the development of motion equations and dynamic equations in the windless state to address the problems of mismatching between vertical and horizontal displacement, and to address the problems of separation trajectory distortion caused by insufficient gravity acceleration of the scaling model of existing light model. The ejection velocity of the model is taken as a factor/vector, and is adjusted reasonably to compensate the linear displacement insufficiency caused by the insufficient vertical acceleration of the light model method, so as to ensure the matching of the vertical and horizontal displacement of the projectile, and to improve the consistency between the test results of high-speed projection and the actual separation trajectory. The optimized Similarity Law is applicable to many existing free-throwing modes of high-speed wind tunnels. The optimized Similarity Law is not affected by the ejection velocity and hanging mode of the projectile. The optimized Similarity Law is suitable not only for the launching of the buried ammunition compartment and external stores, but also for the test design of projectile launching and gravity separation.
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free flight wind tunnel test Similarity Law derivation for light store separation from aircraft
Advances in Mechanical Engineering, 2019Co-Authors: Fei Xue, Zenghui Jiang, Yuchao Wang, Xin Jin, Han Qin, Peng BaiAbstract:Based on the linear displacement motion Similarity and angular displacement motion Similarity, the Similarity Law for free flight test of light store separation from aircraft is deduced. The proble...
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Optimization and verification of wind tunnel free-flight Similarity Law for separation of cluster munition
Chinese Journal of Aeronautics, 1Co-Authors: Fei Xue, Huaqiang Wang, Zenghui Jiang, Yuchao Wang, Han Qin, Jun Tang, Peng BaiAbstract:Abstract In view of the separation form of the separator from the back of the carrier upward and from the side of the carrier outward, separation-safety research is carried out by taking the separation of a cluster munition as an example. In previous wind tunnel free-flight tests, the Similarity Law of vertical, downward, moving submunition was used to design submunitions at different positions in different initial-velocity directions, which resulted in large discrepancies between wind tunnel test results and real flight. In a wind tunnel test, each submunition has an independent time-reduction ratio with respect to the dispenser. Even if the separation trajectory of a single submunition is accurate, there will be errors in the position of each submunition at a given time. Therefore, it is necessary to determine the time-reduction ratio between submunitions, and to modify the test results later. In order to ensure the accuracy of wind tunnel test results, the Similarity Law of a free-flight test in a wind tunnel is derived in this paper. The time-correction scheme to ensure motion Similarity between submunitions is solved. Numerical simulation is used to simulate the separation of a wind tunnel test and real aircraft, and the motion parameters of different submunitions are solved. The results show that the new Similarity Laws derived for different types of submunitions can greatly reduce the errors caused by previous Similarity Laws. In addition to the case for the separation of a cluster munition, the Similarity Law can also be applied to the free-flight test design of wind tunnels for vertical separation and horizontal separation of other kinds of aircraft.
Han Qin - One of the best experts on this subject based on the ideXlab platform.
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optimization and verification of free flight separation Similarity Law in high speed wind tunnel
Chinese Journal of Aeronautics, 2020Co-Authors: Fei Xue, Zenghui Jiang, Yuchao Wang, Xin Jin, Peihua Feng, Han Qin, Peng BaiAbstract:Abstract Based on the Similarity of separation time, a Similarity Law optimization method for high-speed weapon delivery test is derived. The typical separation state under wind load is simulated by the numerical method. The real separation data of aircraft, separation data of previous test methods, separation data of ideal wind tunnel test of previous methods, and simulation data of the proposed optimization method are obtained. A comparison of the data shows that the method proposed can improve the performance of tracking. Similarity Law optimization starts with the development of motion equations and dynamic equations in the windless state to address the problems of mismatching between vertical and horizontal displacement, and to address the problems of separation trajectory distortion caused by insufficient gravity acceleration of the scaling model of existing light model. The ejection velocity of the model is taken as a factor/vector, and is adjusted reasonably to compensate the linear displacement insufficiency caused by the insufficient vertical acceleration of the light model method, so as to ensure the matching of the vertical and horizontal displacement of the projectile, and to improve the consistency between the test results of high-speed projection and the actual separation trajectory. The optimized Similarity Law is applicable to many existing free-throwing modes of high-speed wind tunnels. The optimized Similarity Law is not affected by the ejection velocity and hanging mode of the projectile. The optimized Similarity Law is suitable not only for the launching of the buried ammunition compartment and external stores, but also for the test design of projectile launching and gravity separation.
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derivation and validation of wind tunnel free flight Similarity Law for store separation from aircraft
Aerospace Science and Technology, 2020Co-Authors: Fei Xue, Yuchao Wang, Han QinAbstract:Abstract This paper describes a design method for a Similarity Law for free-flight tests of aircraft load separation. The effect of the initial separation velocity on the motion Similarity is considered. For the first time, the initial separation velocity is introduced into the equation of motion to identify similar trajectories. Finally, the model mass parameter characteristics and separation velocity equation are solved to determine Similarity Laws for wind tunnel tests, greatly improving the accuracy and applicability of test results from wind tunnels. The proposed derivation overcomes the problems faced by the traditional light model method and the traditional heavy model method, namely that they are limited in terms of ejection separation and cannot be realized in wind tunnel tests. The typical separation state under wind load scenarios is simulated using computational fluid dynamics (CFD). Separation data from real aircraft and previous test methods are compared with the simulation data obtained by the new Similarity Law design method. The improvement of the new Similarity Law in terms of trajectory simulation is verified through a comprehensive data comparison. The data show that the new Similarity Law greatly improves the accuracy of wind tunnel tests.
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free flight wind tunnel test Similarity Law derivation for light store separation from aircraft
Advances in Mechanical Engineering, 2019Co-Authors: Fei Xue, Zenghui Jiang, Yuchao Wang, Xin Jin, Han Qin, Peng BaiAbstract:Based on the linear displacement motion Similarity and angular displacement motion Similarity, the Similarity Law for free flight test of light store separation from aircraft is deduced. The proble...
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Optimization and verification of wind tunnel free-flight Similarity Law for separation of cluster munition
Chinese Journal of Aeronautics, 1Co-Authors: Fei Xue, Huaqiang Wang, Zenghui Jiang, Yuchao Wang, Han Qin, Jun Tang, Peng BaiAbstract:Abstract In view of the separation form of the separator from the back of the carrier upward and from the side of the carrier outward, separation-safety research is carried out by taking the separation of a cluster munition as an example. In previous wind tunnel free-flight tests, the Similarity Law of vertical, downward, moving submunition was used to design submunitions at different positions in different initial-velocity directions, which resulted in large discrepancies between wind tunnel test results and real flight. In a wind tunnel test, each submunition has an independent time-reduction ratio with respect to the dispenser. Even if the separation trajectory of a single submunition is accurate, there will be errors in the position of each submunition at a given time. Therefore, it is necessary to determine the time-reduction ratio between submunitions, and to modify the test results later. In order to ensure the accuracy of wind tunnel test results, the Similarity Law of a free-flight test in a wind tunnel is derived in this paper. The time-correction scheme to ensure motion Similarity between submunitions is solved. Numerical simulation is used to simulate the separation of a wind tunnel test and real aircraft, and the motion parameters of different submunitions are solved. The results show that the new Similarity Laws derived for different types of submunitions can greatly reduce the errors caused by previous Similarity Laws. In addition to the case for the separation of a cluster munition, the Similarity Law can also be applied to the free-flight test design of wind tunnels for vertical separation and horizontal separation of other kinds of aircraft.
A E Perry - One of the best experts on this subject based on the ideXlab platform.
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Similarity Law for the streamwise turbulence intensity in zero pressure gradient turbulent boundary layers
Physics of Fluids, 1997Co-Authors: Ivan Marusic, A K M Uddin, A E PerryAbstract:A Similarity relationship is proposed to describe the streamwise broadband-turbulence intensity in a zero-pressure-gradient boundary layer. The formulation is applicable to the entire region of the flow beyond the viscous buffer zone and is based on the attached eddy hypothesis, the Reynolds-number-Similarity hypothesis and the assumed existence of Kolmogorov eddies with a universal inertial subrange. Experimental data of the authors and those from various published works covering a large Reynolds number range are investigated in light of this formulation.
