简介:声学的散布从沉没由一个事件飞机波浪的充满液体的有限的圆柱的壳insonified试验性地并且理论上被学习。有锋利的择向性的一个monostic宽带变换器在实验被使用。宽带LFM信号和单个频率的狭窄的脉搏被用来测量圆柱的壳的backscattering领域。测量结果及时与理论有一个好协议并且频率领域。理论、试验性的结果证明被内部液体引起的几个另外的波浪的回声在频率领域被介绍。并且波浪生产的一系列低语的画廊波浪在填的内部液体来回思考了圆柱的壳被增加。为在频率角度光谱聚类碗形状回声曲线的原因作为低语的画廊波浪的开始的几个模式的重叠被解释。
简介:BasedonthetheoreticalanalysisofastandingwavetubewithflowandlateralHelmholtzresonator,arelevantexperimentalapparatusweresetup,andweresuccessfullyusedtovalidatethetheanalysisabove.Meanwhileanendcorrectionandanequivalentradiuscoefficientcoveredinthetheoreticalanalysiswerealsodeterminedbyexperiments.FurthermoreseveralresultsobtainedfromthetheoreticalanalysisandexperimentswereusedtodiscusstheeffectsofflowontheperformanceofHelmholtzresonatorandthesoundfieldinthestandingwavetube.ItisshownthatusingHelmholtzresonatorforthestandingwavetubewithflowisstillagoodmeasurefornoisereduction,eventhoughtheeffectofnoisereductioncouldbereducedbecauseofflow.