Department of Mechanical Engineering and Mechanics, Drexel University, Philadelphia, Pennsylvania 19104, USA.
J Acoust Soc Am. 2013 Aug;134(2):917-32. doi: 10.1121/1.4807635.
A high fidelity computational fluid dynamic model is used to simulate the flow, pressure, and density fields generated in a cylindrical and a conical resonator by a vibrating end wall/piston producing high-amplitude standing waves. The waves in the conical resonator are found to be shock-less and can generate peak acoustic overpressures that exceed the initial undisturbed pressure by two to three times. A cylindrical (consonant) acoustic resonator has limitations to the output response observed at one end when the opposite end is acoustically excited. In the conical geometry (dissonant acoustic resonator) the linear acoustic input is converted to high energy un-shocked nonlinear acoustic output. The model is validated using past numerical results of standing waves in cylindrical resonators. The nonlinear nature of the harmonic response in the conical resonator system is further investigated for two different working fluids (carbon dioxide and argon) operating at various values of piston amplitude. The high amplitude nonlinear oscillations observed in the conical resonator can potentially enhance the performance of pulse tube thermoacoustic refrigerators and these conical resonators can be used as efficient mixers.
使用高保真计算流体动力学模型模拟由振动端壁/活塞产生的高振幅驻波在圆柱形和圆锥形谐振器中产生的流动、压力和密度场。发现圆锥形谐振器中的波是无激波的，并且可以产生超过初始未扰压力两到三倍的峰值声超压。当另一端声学激励时，圆柱形（谐音）声学谐振器对在一端观察到的输出响应存在限制。在圆锥形几何形状（不谐音声学谐振器）中，线性声学输入转换为高能量的未激波非线性声学输出。该模型使用过去在圆柱形谐振器中驻波的数值结果进行了验证。对于在不同活塞振幅下工作的两种不同工作流体（二氧化碳和氩气），进一步研究了圆锥形谐振器系统中谐波响应的非线性性质。在圆锥形谐振器中观察到的高振幅非线性振荡有可能提高脉管热声制冷机的性能，并且这些圆锥形谐振器可用作有效的混合器。
