将钻柱简化为理想周期性管结构,利用有限差分方法,对不同频率的正弦声信号在周期性管结构中传输过程中,存在透射系数及衰减系数差异较大的现象进行数值模拟与分析,得到不同频率的正弦声信号穿过周期性管结构后信号的时域及频域分布.分别对400 Hz和500 Hz的正弦声信号在周期性管结构中传输进行了模拟.模拟结果表明:处于带通频率的正弦声信号在周期性管结构中传播波形失真小,频谱变化小,传播性能良好;带阻频率的正弦声信号在周期性管结构中传播波形失真严重,频谱变化很大,几乎不能通过.模拟结果与同类研究成果有较好的一致性.验证该模型和所采用的数值方法的有效性,为钻柱中声信号传输的数值模拟及与其类似的实际问题的数值模拟提供参考.
The drill string is simplified as ideal periodic tube structure. Finite difference method is employed to simulate and analyze the phenomenon of large differences between transmission coefficient and attenuation coefficient during transmission process of sinusoidal signal of different frequency along the periodic tube structure. The distributions in time domain and frequency domain respectively of the signal after transmission through the periodic tube structure from sine signal of different frequency through the periodic tube structure are obtained. Then using this method the transmission of sinusoidal acoustic signal of 400 Hz and 500 Hz in a periodic tube structure, has been simulated. The results show that waveform distortion and spectrum variation are small and transmission is good for the sinusoidal signal of pass band frequency, but waveform distortion is severe, spectrum variation significant and transmission are bad for the sinusoidal signal of block band frequency. The simulation results have good consistency with that of other similar research. The feasibility and validity of the finite difference method presented in this paper are verified.