Spanwise-Discontinuous Grooves for Separation Delay and Drag Reduction of Bodies with Vortex Shedding

Suitably shaped grooves, placed transverse to the flow, can delay flow separation over curved surfaces. When grooves are fully extruded in spanwise direction, they may reduce drag of boat-tailed bodies with vortex shedding, but drawback increasing correlation shedding. We investigate herein effect spanwise-discontinuous through Large Eddy Simulations. A systematic analysis is carried out on number, N, that present for N equally long portions total length boat-tail. Discontinuous further compared full-spanwise-extruded groove. Increasing produces an improvement flow-control-device performance, whose maximum value reached N=3, corresponding a extension groove roughly equal body crossflow dimension. Above this value, no improvements found. The reduction 25.7% boat-tail without and 17.7% one lowest occurs least correlated vortex-shedding direction. mainly related line less regular