A thin plate is moving in still atmosphere air at a velocity of 5m/s. The length of the plate is 0.6m and width 0.5m.

Calculate :

1. Thickness of Boundary Layer at the end of the plate

2. Drag force on one side of the plate.

Take density of air $1.24 kg/m^3$ and kinematic viscosity 0.15 stokes.

Solution :

Given :

Velocity of plate, $\quad u=5 \mathrm{~m} / \mathrm{s}$

Length of plate, $\quad L=0.6 \mathrm{~m}$

Width of plate, $\quad b=0.5 \mathrm{~m}$

Density of air, $\quad p=1.24 \mathrm{~kg} / \mathrm{m}^{3}$

Kinematic viscosity, $\quad v=0.15$ stokes

$=0.15 \times 10^{-4} \mathrm{~m}^{2} / \mathrm{s}$

Reynold number,

$\begin{aligned} \quad R_{e}&=\frac{u L}{{v}}=\frac{5 \times …