# Separate Drag cofficient to 2 coefficient

1. May 7, 2012

### Multiface

1. The problem statement, all variables and given/known data
I've been given the mission to find out the drag coefficient for the Ahmed Body. The drag coefficient itself it too hard to measure. The problem for me is to find a way to separate the drag coefficient to Pressure Drag coefficient and Skin friction coefficient.

My question is: How can I with the help of different instruments measure Pressure Drag c. and the Skin Friction Drag separately??

Multiface

F = C * ρ * A * v^2

F = Drag force
C = Drag coefficient
A = Area projectet in the flow-direction
v = velocity of fluid

2. May 8, 2012

### PhanthomJay

The drag equation is F = 1/2(C)(ρ)(A)v^2 (you left off the one-half).

I would think it would be very difficult to separate the pressure and skin friction drags. I believe in calculating various automobile drag coefficients, which include both effects, that often an equivalent drag-area coefficient (C*A) term is used, where A is more than just the projected frontal area. But I/m unsure.