基于滤波器方法主动吸收式数值水槽研究

Study on active absorption numerical flume based on filter method

基于开源程序OpenFOAM,采用动边界法进行造波,通过求解N-S方程建立二维粘性数值波浪水槽。针对二次反射波,采用频域滤波器方法进行吸收,综合考虑理论传递函数及实际造波需要,确定了目标水深下合适的滤波器参数。通过固定位置输出动边界开发了主动吸收式造波边界,以造波板上理论波面和实测波面为输入信号,根据差分方程得到造波板位移,控制边界运动吸收二次反射波。对比分析不同周期下规则波和不规则波的造波质量,证明了频域滤波器法主动吸收的正确性和可靠性,为此方法在实际物理模型实验中应用提供了理论依据。

Based on the open source program OpenFOAM,a two-dimensional numerical wave flume considering viscosity was established by solving the N-S equation,in which the moving boundary method was adapted to make waves.Considering both practical wave-making needs on accuracy and the theoretical transfer function,the frequency domain filter method was investigated on the effect of absorbing secondary reflection wave,aiming to determine the appropriate filter parameters under the target water depth.The actively absorbing wave-making boundary was newly developed by inheriting the fixed ValuePointPatchField of moving boundary.The theoretical wave series and the measured wave series through the wave-making plate were taken as input signals,and then the related difference equations were solved to obtain displacements of the wave-making plate,so as to control the movement of the boundary and absorb the secondary reflection wave.By analyzing the results of generating regular wave and irregular wave in different periods,active absorption methods based on the frequency domain filter were proven accurate and robust,which can provide a basis for the application of this method in actual physical model experiments.