The aim of this work is to investigate the comparative effect of two passive flow controls in modifying the mean wake topology around a simplified square back vehicle model. The two passive flow controls are (i) Single cavity and (ii) Multicavity. A straight cavity with an optimum depth at the rear base of a vehicle is a well known technique used to alter the mean wake topology and achieve drag reduction. For two dimensional bluff bodies multicavity is known to achieve better drag reduction at shorter cavity depths in comparison to single cavity. With this view point, a numerical investigation is carried out to examine the performance of multicavity over single cavity in drag reduction for a three dimensional bluff body vehicle model. The numerical simulations are performed at Reynolds Number (Re) = 1×10^5^ using the k-ω SSTSAS turbulence model in a  Finite volume open source code OpenFOAM. The investigations revealed, for any cavity depth, single cavity always performed better than multicavity in reducing drag. Hower at optimum cavity depth equal to 33% of the body height the drag reduction magnitude was identical for both the flow controls. The plausible mechanisms responsible for their relative difference in performance will be explored by analysing the base pressure distribution, wake mean topology and the temporal behaviour of the wake.


Numerical Investigation of a Square Back Ahmed Body Equipped With a Single Cavity and Multi-Cavity

Division / Sponsors: 
Heat Transfer Division (HTD), Fluids Engineering Division (FED)

Heat Transfer Summer Conference
Paper Proceedings: https://asmedigitalcollection.asme.org/HT/HT2020/volume/83709

18th International Conference on Nanochannels, Microchannels, and Minichannels
Paper Proceedings: https://asmedigitalcollection.asme.org/ICNMM/ICNMM2020/volume/83693

Fluids Engineering Division Summer Meeting
Paper Proceedings: https://asmedigitalcollection.asme.org/FEDSM/FEDSM2020/volume/83716

HT-ICNMM2020 - Virtual Conference, SHTC - Virtual Conference, FEDSM2020 - Virtual Conference

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