Question

A 1/4th scale car is to be tested in a wind tunnel. If the full scale speed of the car is 30m/s, what should be the wind tunnel speed for Reynolds number similarity a) 30m/s b) 6m/s c) 7.5m/s d) 150m/s e) 120m/s

Answer 1

Answer:

e)v=120 m/s

Explanation:

Given that

Scale ratio = 1/4

Speed of car =30 m/s

lets wind tunnel speed is v

We know that Reynolds number given as

$Re=\dfrac{\rho\ L\ V}{\mu }$

If all conditions taken as similar then

$(L\ V)_c=(L\ V)_w$

Given that

$\dfrac{L_w}{L_c}=\dfrac{1}{4}$

So we can say that

4 x 30 = v x 1

v=120 m/s