Numerical Modeling of Thermo-Acoustic Streaming

Abstract

The thermo-acoustic streaming is a new type of convection that has been discovered experimentally under micro-gravity in our past work. The convection occurred when a droplet burns in a standing sound wave. When the droplet is placed between a node and an anti-node, the flame is flown in one direction. The flow is the ‘‘thermo-acoustic streaming’’. The detailed data on the flow field of the streaming does not exist sufficiently. The fields have no ways to be analyzed besides DNS so far. Since the DNS requires a long computational time, a new numerical model with time-averaged quantity is desired. To develop the time average model of the thermo-acoustic streaming, we have analyzed the time variation of temperature distributions on the streaming. It has been confirmed that a force based on the acoustic radiation force is the key to build the time average model. The force is taken into account to the Reynolds equation. The time average model has been named ‘‘ARF model’’. The DNS data are compared with the experimental data, and the ARF model data are compared with the DNS data. We have clarified that the ARF model can be developed using the acoustic radiation force with appropriate constant and allows low calculation cost.