Question

2.19 The drag characteristics of a blimp traveling at 4 m/s are to be studied by experiments in a water tunnel. The prototype is 20 m in diameter and 110 m long. The model is one-twentieth scale. What velocity must the model have for dynamic similarity

Answer 1

Answer:

$Vm=0.894m/s$

Explanation:

From the question we are told that

Velocity if travel $v=4m/s$

Diameter of  prototype $d_1=20m$ and $d_2=110m$

Scale ratio=$\frac{1}{20}$

Generally Velocity of of the model using Froud's model is mathematically given as

$Fm=Fp$

$\frac{Vm}{\sqrt{Lmg}} =\frac{Vp}{\sqrt{Lpg}}$

$Vm=Vp*\frac{Vp}{\sqrt{Lpg} }$

$Vm=4*\frac{1}{\sqrt{20}}$

$Vm=0.894m/s$