On Oscillation of a Confined Jet With a Downstream Obstacle Available to Purchase

In the present study, the authors investigate an oscillatory phenomenon of a two-dimensional confined jet with a square prism, by experiments and computations. In experiments in an air duct, jet’s frequencies were measured near the target by a hot-wire anemometer, in the Reynolds-number range of 300–5000. In computations, the numerical method adopted here is a finite difference method formulated in terms of vorticity and stream function. As a result, we can see the Reynolds-number effect, the target-distance effect and the target-size effect upon Strouhal number. Regarding the Reynolds-number effect, it was found that there is less influence, which guarantees widerange workability as a flowmeter or a mixer. Regarding geometrical parameters, the results show information for optimal configurations. The results can be surnmarised in an empirical formula describing the relation between Strouhal number and geometrical parameters, with a specified unstable range. Computed jet’s frequencies were confirrned to be in good agreement with experimental ones, which indicates that the phenomenon is intrinsically two-dimensional. Numerical results reveal details of flow field and possibility for applications.