In this paper, the effects of the passive technique using the slotted wall with cavity on the characteristics of a steady condensation shock wave generated in a Prandtl-Meyer flow were investigated experimentally. Furthermore, in order to clarify the variation of condensate properties in the flow field, Navier-Stokes equations were solved numerically using a 3rd-order MUSCL type TVD finite-difference scheme. From experimental results, it was found that the strength of steady condensation shock wave in case with passive control using the slotted wall with cavity was suppressed in comparison with no passive case (solid wall), and the present passive technique was the most effective when a foot of the condensation shock wave was located at the middle of slotted wall. Furthermore, the unsteady condensation shock wave in the Prandtl-Meyer expansion fan was simulated and it was confirmed numerically that the passive technique was also effective for controlling of an unsteady condensation shock wave.

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Thermal propagation in heat spreader is observed and investigated with numerical visualization technique comparing with the analytic modeling. From the numerical results, three different modes of 3-D thermal propagation are found and are verified with the analytic model. Transient spreading phenomena in limited thickness with constant heat transfer boundary has not yet been modeled for various heat input as time function. The observation provides the behavior of the individual stage of transient spreading and the basis of the approximate function which fits the numerical calculation over the practically wide range of time. The approximation is done by simulated electrical circuits so that any time-function for heat input is able to be analyzed.

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