Free flight wind tunnel test similarity law derivation for light store separation from aircraft

Xue, Fei; Qin, Han; Wang, Yuchao; Jiang, Zenghui; Jin, Xin; Bai, Peng

doi:10.1177/1687814019853062

Cited by 9 publications

(4 citation statements)

References 12 publications

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“…2022, 12, x FOR PEER REVIEW 4 research scope and ensuring its accuracy. Meanwhile, Xue et al [27,28] also condu exploratory research on jet characteristics. Model free-flight wind tunnel and traditional jet control test methods each have tain advantages.…”

Section: Test Model and Fd-12 Wind Tunnel 21 Test Modelmentioning

confidence: 99%

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Solving the Moment Amplification Factor of a Lateral Jet by the Unsteady Motion Experimental Method

Xue

Zhang²,

Cao

et al. 2022

Applied Sciences

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In this paper, unsteady motion tests of a lateral jet adjusting an air vehicle’s attitude are carried out. Curves of pitch moment amplification factors (KM) for a lateral jet versus angle of attack (α) are obtained using a wind tunnel free-flight test technique with a jet and data processing method. This new method overcomes the disadvantage of previous experiments that can study only one unsteady characteristic. The free-flight test technique in the proposed method ensures that the test model can be coupled in real-time with multiple parameters (unsteady flow caused by the jet, unsteady air vehicle aerodynamic force, and unsteady air vehicle motion). This approach simulates an actual air vehicle’s complete jet test process and ensures more authentic and reliable test results. In the new data processing method, continuous data curves are fitted to discrete data points, making it easier to convert the angular displacement versus time curve into the pitch moment versus α curve to obtain KM. The results show that when the pressure of the micro high-pressure gas cylinder is 2.0 MPa, KM is below 1, indicating that the lateral jet does not significantly promote the pitching moment. When the gas cylinder pressure is 4.0 MPa and the angle of attack is 5° < |α| < 16°, KM is greater than 1, and the lateral jet promotes the pitching moment. When 16° < |α| < 20°, KM is less than 1, and the lateral jet does not significantly contribute to the pitching moment. It was further found that KM decreases slowly with increasing α. When |α| > 30°, the influence of the jet on the pitching moment nearly disappears.

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Section: Test Model and Fd-12 Wind Tunnel 21 Test Modelmentioning

confidence: 99%

“…In recent years, Xue et al [23][24][25][26] have greatly improved the former wind tunnel free-flight test technique and test theory, expanding the research scope and ensuring its accuracy. Meanwhile, Xue et al [27,28] also conducted exploratory research on jet characteristics.…”

Section: Introductionmentioning

confidence: 99%

Solving the Moment Amplification Factor of a Lateral Jet by the Unsteady Motion Experimental Method

Xue

Zhang²,

Cao

et al. 2022

Applied Sciences

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“…In recent years, Xue et al 20,21 have greatly improved and improved the previous wind tunnel free flight test technique and test theory, which not only expands the research scope of wind tunnel free flight test, but also ensures the accuracy and accuracy of wind tunnel free flight test. Meanwhile, Xue et al [22][23][24][25] also carried out exploratory research on jet characteristics.…”

Section: Introductionmentioning

confidence: 99%

Unsteady test technique of jet control with multi-parameter coupling

Xue

Cao

et al. 2022

Advances in Mechanical Engineering

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In this paper, the jet control effect of air vehicle is studied, and a new multi parameter coupling unsteady test technique is established, which can ensure that the test model is consistent with the real air vehicle, and the jet is carried out under the condition of complete freedom and no support constraints, so that the wind tunnel test can better simulate the jet control effect of real air vehicle. The new technique overcomes the shortcoming that the previous jet test can only carry out unsteady flow field or unsteady aerodynamic force research, and can ensure that in the whole process of jet flow, the interference flow field at the nozzle, the aerodynamic force of the air vehicle, especially the movement of the air vehicle, are coupled with each other all the time, so as to achieve the same effect as the real air vehicle. The establishment of the new technique overcomes many problems, including the total length of the model is 167 mm, no support for the model, storage of small volume/high-pressure gas in free state, on-time unlocking of sealed gas source in free state of the model, and connection of gas source and nozzle in the model. The test results show that when no jet, the revolution body is head up, which affected by the cavity shock wave. When jet on, the jet force continues to act on the revolution body, resulting in the revolution body lowering its head until it diverges. The new technique can achieve more advanced technical indicators, including: ensuring jet Mach number >1; Ensure that the static pressure ratio of the jet is more than 10 (the static pressure ratio can be greater at hypersonic speed). After the establishment of the new technique, the supersonic wind tunnel test is carried out, and the ideal test results are obtained, which shows that the new technique is reliable.

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“…A problem corresponding to analyzing the dynamic separation of multiple bodies in the air is mostly related to store separation from aircraft [16,17], for example, the separation of the X-15 research vehicle from the B-52 carrier aircraft [18,19]. In such cases, the store and the X-15 vehicle are much smaller than that of the parent vehicle.…”

Section: Introductionmentioning

confidence: 99%

A Nonlinear CFD/Multibody Incremental-Dynamic Model for A Constrained Mechanism

Rahmati

Karimi

2021

Applied Sciences

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Numerical analysis of a multibody mechanism moving in the air is a complicated problem in computational fluid dynamics (CFD). Analyzing the motion of a multibody mechanism in a commercial CFD software, i.e., ANSYS Fluent®, is a challenging issue. This is because the components of a mechanism have to be constrained next to each other during the movement in the air to have a reliable numerical aerodynamics simulation. However, such constraints cannot be numerically modeled in a commercial CFD software, and needs to be separately incorporated into models through the programming environment, such as user-defined functions (UDF). This study proposes a nonlinear-incremental dynamic CFD/multibody method to simulate constrained multibody mechanisms in the air using UDF of ANSYS Fluent®. To testify the accuracy of the proposed method, Newton–Euler dynamic equations for a two-link mechanism are solved using Matlab® ordinary differential equations (ODEs), and the numerical results for the constrained mechanisms are compared. The UDF results of ANSYS Fluent® shows good agreement with Matlab®, and can be applied to constrained multibody mechanisms moving in the air. The proposed UDF of ANSYS Fluent® calculates the aerodynamic forces of a flying multibody mechanism in the air for a low simulation cost than the constraint force equation (CFE) method. The results could have implications in designing and analyzing flying robots to help human rescue teams, and nonlinear dynamic analyses of the aerodynamic forces applying on a moving object in the air, such as airplanes, birds, flies, etc.

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Free flight wind tunnel test similarity law derivation for light store separation from aircraft

Cited by 9 publications

References 12 publications

Solving the Moment Amplification Factor of a Lateral Jet by the Unsteady Motion Experimental Method

Solving the Moment Amplification Factor of a Lateral Jet by the Unsteady Motion Experimental Method

Unsteady test technique of jet control with multi-parameter coupling

A Nonlinear CFD/Multibody Incremental-Dynamic Model for A Constrained Mechanism

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