Chapter 7, Problem 7.9P

Note: In the following problems, you will deal with both the International System of Units (SI) (N, kg, m, s, K) and the English Engineering System (lb, slug, ft, s, $°\text{R}$). Which system to use will be self-evident in each problem. All problems deal with calorically perfect air as the gas, unless otherwise noted. Also, recall that $1\text{atm}=2116{\text{lb/ft}}^{\text{2}}=1.01\times {10}^5{\text{N/m}}^{\text{2}}$.

An airfoil is in a freestream where $p_{\infty }=0.61\text{atm,}{\rho }_{\infty }=0.819{\text{kg/m}}^{\text{3}}$, and $V_{\infty }=300\text{m/s}$. At a point on the airfoil surface, the pressure is 0.5 atm. Assuming isentropic flow, calculate the velocity at that point.