Some examples on the similarity of compressible flows are studied by solving the basic equation expressed with the independent variables of stream velocity and stream function. The similarity is discussed in the flow field and on the hodograph plane. The results are : (1) the similarity is recognized in the flow field as well as on the hodograph plane for the case of a sink flow, a spiral flow, and the Prandtl-Meyer flow, (2) it is seen only on the hodograph plane for the case of the supersonic flow along a curved wall, and (3) it is also seen in the vicinity of the sonic line for the case of the transonic flow in a curved channel.

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A simple method of adjusting lineariser constants for a constant-temperature hot-wire was proposed. As an extension of the 2 point calibration method by the present author, it features itself by setting A and n in the e²=A+Buⁿ type equation so that the equation exactly fits the calibration points at 3 different wind velocities, all of them being in the range of actual interest ; there is no need for referring to the unreliable null velocity condition. The circuitry and procedure are quite simple.

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Reflection of internal waves at the interface between the mixed layer and a stratified fluid is experimentally investigated. Reflection coefficients of the internal waves and transmission coefficients of interfacial waves are obtained through experiments, where the interfacial waves propagate along the interface. In order to reveal the energy budget of the two kinds of waves, the reflection and transmission coefficients are adopted in consideration of wave dissipation. Where a ratio of the frequencies of the interfacial and internal waves is 1/2, 1 or 2 with the same horizontal wavenumber, the over-reflection takes place (i.e. reflection coefficient >1), while under the same condition the transmission coefficient of the interfacial wave is less than unity. Therefore, it is estimated that the energy source of the over-reflection of the internal wave is the interfacial wave. When the two kinds of waves have the identical frequencies and are in phase, over-reflection also takes place. On the other hand, the interfacial wave over-transmits the energy (i.e. transmission coefficient >1), where the phases of the two kinds of waves are inverse to each other.

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