Method for simulating aircraft rock movement with RANS/LES (Reynolds average numerical simulation)/LES (large eddy simulation) mixing technique

Abstract

The invention discloses a method for simulating aircraft rock movement with an RANS / LES (Reynolds average numerical simulation) / LES (large eddy simulation) mixing technique, and aims to solve the problem about self-excitation rock movement under the condition that wide-range separated flow of an aircraft cannot be accurately simulated in the prior art. The method mainly comprises steps as follows: a length scale of a turbulence model is appropriately corrected on the basis of a conventional unsteady RANS method, and DES (detached eddy simulation) methods are constructed; tightly coupled solution of a flow field governing equation and a rigid body motion equation is realized in the dual-time-step pseudo time iteration process with adoption of a prediction-correction algorithm, and the changing course of aerodynamic parameters and motion parameters of the aircraft with time is obtained. On the premise that certain computational efficiency is guaranteed, self-excitation rock motion of the aircraft under the complicated flowing condition is more accurately simulated, and an effective means is provided for nonlinear coupling property evaluation of aerodynamic motion / movement of the aircraft.

Description

technical field [0001] The invention relates to an aircraft aerodynamic simulation method, in particular to a method for simulating the rock motion of an aircraft by using RANS / LES hybrid technology. Background technique [0002] Rock is an aerodynamic / kinematic coupling phenomenon that is often encountered in modern fighter jets and missile weapons. It is the oscillatory motion of the aircraft in the roll direction. In some cases, along with the roll oscillation, the yaw direction will also oscillate, which is called Dutch-roll. As the angle of attack increases, the Dutch roll gradually evolves into a rock and roll movement dominated by roll. Rock motion usually occurs in the form of Limit Cycle Oscillation (LCO). Limit cycle oscillation means that the energy change of motion within a period is zero, that is, the absorbed energy is equal to the dissipated energy, and the oscillation neither diverges nor converges, forming equal-amplitude and equal-period oscillations. Th...

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Problems solved by technology

[0009] At present, the RANS / LES hybrid technology is mainly used in the unsteady separation flow calculation of the static model or specified motion mode, and has not been used in the aerodynamic / kinematic coupling calculation. In the former, the calculation result at the previous moment only affects the flow at the next moment. field evolution, and in the latter case also affects the model motion at later moments

The RANS / LES hybrid method will introduce more airflow pulsation information. Compared with the traditional unsteady RANS method, the convergence speed will be slower and the calculation error will increase. The influence of attitude motion can easily lead to wrong results in the simulation

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