Tests for Validation Problems of Anomalous Separated Flow and Heat Transfer Enhancement on Structured Surfaces with Extraordinary Pressure Drops

Abstract

New tests are presented for application packages and turbulence models for validation problems of high-intensity vortex flows near structured energy-efficient surfaces. The idea of testing is based on the discovery of anomalous intensification of separated flows and heat transfer in inclined grooves on plates and channel walls. In the grooves, due to the extraordinary pressure drops, confirmed by experiments, swirling flows are generated with high velocities of the return and secondary flow, comparable to the speed of the external flow. Also, high-gradient zones with friction and heat transfer are formed inside the grooves, many times (from 1.5–2 to 7–9 times) exceeding friction and heat transfer on a flat wall. As an example, the VP2/3 package, developed on the basis of original multi-block computing technologies and using multi-scale intersecting grids, is being tested. Comparison of numerical predictions with Zubin’s experiments confirmed high static pressure drops between the stagnation zone on the windward slope of the inclined groove and the negative pressure region at the site of generation of a tornado-like flow on the inlet spherical segment, and also demonstrated the acceptability of the RANS approach for predicting the characteristics of high-intensity swirling flows.