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Abstract According to the Riemann invariant and Euler equations solution using a multi-block patched grid, and adopting the perturbation relation among downwash-Lag derivatives, the time rate of change of non-dimensional total angle of attack or deflection angle of each fin, and time rate of change of non-dimensional aerodynamic roll attitude, a method for rapid computation of Downwash-Lag derivatives has been developed in this study. The SDM dynamic derivative standard model was taken as an example to verify the method. The calculated results were in well agreement with the reference data. It has been proven with less runtime, higher accuracy and is useful in engineering. It can also be used to fasten the calculation of the downwash-Lag derivatives of flying vehicles with complicated configurations. This method was tested to obtain the pith rotation derivative and downwash-Lag derivative of SDM standard mode at a 5-degree angle of attack in the sub-/transonic/supersonic range. The results present a particular difference between the results in whether to consider the time difference in the sub-/transonic range, and the influence of downwash-Lag gradually decreases with the increase of the incoming Mach number, and this can be ignored under supersonic conditions.
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Received: 30 June 2023
Published: 28 September 2023
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2023, Vol. 6 
