# Calculate the pressure coefficient at a point on the airfoil.

Calculate the pressure coefficient at a point on the airfoil where the pressure is $$8.9 \times 10^4\,N/m^2$$. Airfoil is in freestream velocity of $$40\,m/s$$ and is at standard sea – level conditions.

Asked on 12th January 2021 in

Pressure coefficient is given as

${C_p} = \frac{{p\, – \,{p_\infty }}}{{{q_\infty }}}$

Dynamic pressure,

${q_\infty } = \frac{1}{2}{\rho _\infty }V_\infty ^2 = \frac{1}{2} \times 1.225 \times {\left( {40} \right)^2} = 980$

Therefore, $$C_p$$ is

${C_p} = \frac{{0.89 \times {{10}^5} \,-\, 1.01 \times {{10}^5}}}{{980}} =\, – 12.24$