# Find the circulation on the airfoil.

An airfoil generates a lift of 80 N when operating in a free stream flow of 60 m/s.If the ambient pressure and temperature are 100 kPa and 290 K respectively ( specific gas constant is 287 J/kg-K),the circulation on the airfoil is

Asked on 30th September 2019 in

Here first we need to calculate the air density.

$$P=\rho RT \\\rho =\frac{P}{RT} \\=\frac{10^{5}}{287\times 290} \\=1.2014\;kg/m^{3}$$

On applying Kutta-Joukowski theorem:

$${L}’=\rho V\tau \\\Rightarrow \tau =\frac{80}{1.2014\times 60} \\=1.11\;m^{2}/s$$

Therefore circulation on the airfoil is $$1.11\;m^{2}/s$$.