|April 19, 2017, 12:30||
Reducing drag on a bluff body using dimples
Join Date: Apr 2017
Location: New Delhi
Posts: 1Rep Power: 0
I am performing simulations on an Ahmed body (bluff body) having significant amount of pressure drag and trying to control it using dimples on its surface(Top as well as slant face).
I understand that the problem is one with laminar flow over the surface which transitions to turbulent conditions under the effect of dimples as irregularities and theoretically should result in a reduction of drag value.
But the problem is that we are not able to achieve any drag reduction at all. Drag is always a bit higher than the nominal value, always a bit HIGHER( We have exhausted all the k-e wall treatment options scalable as well as enhanced wall treatment, the low Re number k-w approach with yplus=1 and the 4 eqn transition SST model for our case and still unable to get a reduced drag value).
I would like to know how to tackle the above problem in order to get tangible results.
Just to give you an idea, the dimple dimensions are like 30mm dia with 6mm depth incorporated over a body having a length of 1044mm.
Mesh is about 5.3 million.
Orthogonality is less due to high aspect ratio cells near the wall.
Turbulence intensity at inlet is 1%
Turbulence intensity at Outlet is 5%
Turbulent viscosity ratio is kept at its default value 10 for both inlet and outlet.
Which turbulence modelling to choose (RANS) and with what settings ?
|Thread||Thread Starter||Forum||Replies||Last Post|
|[ANSYS Meshing] Reducing mesh non-orthognality for bluff body with sharp edges||Bashar||ANSYS Meshing & Geometry||2||November 18, 2016 03:28|
|Reducing Ship Drag with Air Bubbles||tmeysam92||FLUENT||0||September 15, 2016 01:02|
|Reynolds Stress Models for bluff body flows||siw||CFX||1||March 4, 2016 06:58|
|Ahmed body -Drag coefficient not converging!!||sam92||FLUENT||10||February 25, 2016 09:31|
|convergence problem / bluff body / k omega||LM4112||OpenFOAM Pre-Processing||3||June 16, 2013 06:28|