RANS-based design of experimental flow model for investigation of complex curved turbulent wakes subjected to adverse pressure gradient

Results are presented of a series of RANS computations aimed at creating a new experimental flow model of a curved turbulent wake evolving under adverse pressure gradient. In the course of the computations, key geometric parameters of the model (the angle of attack of a flat plate generating the wake and the shape and the angles of attack of liner foils creating the pressure gradient) were varied in a wide range. The purpose was to find the parameters ensuring desirable features of the flow, namely, a considerable wake curvature and its strong deceleration leading to formation of a large stagnation or even a reversal flow region, on the one hand, and no flow separation either from the flat plate or from the surfaces of the liner foils, on the other hand. As a result, the design satisfying all these demands has been found. This design will be implemented and studied in the framework of recently launched joint German-Russian project “Complex Wake Flows” which presents a continuation of an earlier similar project devoted to symmetric wakes.

Effect of Gust Wind on Flow over a Wall-Mounted Fence

In this work, the characteristics of incoming and wake flows downstream of wall-mounted fences under wind gust were explored with wind tunnel experiments. A time-resolved particle image velocimetry was used to capture the flow dynamics across two different fence heights. The results show that during the gust period, the wake presents distinct meandering and strong flow mixing. The Probability Density Function distribution of flow velocities indicates that the mixing effect increases with the streamwise distances. Specifically, for locations above the fence top tip, the growth of streamwise distance decreases the footprint of wind gust. However, for locations lower than the fence top tip, the local wind flows exhibit stronger variations before and after wind gust with the growth of downstream distance. Overall, at the same relative streamwise and spanwise locations downstream of fences within the wake region, the higher fence better suppresses the influence of gust wind.