Based on the method of LES (large eddy simulation) and FWH (Ffowcs Williams-Hawkings), the aerodynamic noise of corrugated tubes in 3D model was simulated and calculated, which was consistent with the theoretical value and experimental value. Comparing the results of parametric calculation and analysis of corrugated depth, the research results show that: ① when the air flowing through corrugated tubes, the maximum of the absolute pressure appears at the corrugated pitch point and the minimum appears at the corrugated ventral point. ② The average of surface sound pressure of aerodynamic noise increases as the axial distance increasing. ③ The sound pressure level and the mean power spectral density first increase and then decrease as the corrugated depth increasing. The numerical calculation method in this paper has potential application value in the field of duct noise processing.

Based on the theory of air convection formed by candle burning and 3D model of Abstractflat-plate flow at high angle of attack, the relevant theoretical analysis, experimental exploration and numerical simulation analysis of the design topic “Candle Powered Turbine” at the 2022 International Young Physicists' Tournament are carried out in a targeted manner. Combined with the model of air convection formed by candle burning, and the three-dimensional model of flat-plate flow at high angle of attack is generalized and applied, the theoretical formula of the torque of the paper spiral in the flow field generated by candles is obtained. The influence of the width and the axial inclination angle of the paper tape on the torque of the paper spiral is explored through experiments, and the optimized parameters are obtained. CFD numerical simulation analysis and experimental research are carried out on the optimized device. The simulation results are in good agreement with the experimental results, which confirms the accuracy of the torque theory proposed in this paper for the motion of paper spirals in the air flow field formed by candle combustion, The natural convection formed by fuel combustion is used as the power source in the rotating device, which has potential application value for the utilization of surplus energy. Moreover, the establishment of the 3D model of flat plate flow at high angle of attack provides a simple calculation method for the total pressure calculation of the flow around a three-dimensional flat plate at a low speed at a high angle of attack with Reynolds number in the range of 10⁴~10⁶.