Definition of stagnation speed of sound:驻点音速的定义 (8.3) y-12y (8.34) 12y-12y-11 2 1 2 0 2 2 − + =  −  a u a 1 2 1 2 1 2 0 2 2 2 2 2 1 2 1 − + = − + =  −   a u a u a Definition of stagnation speed of sound：驻点音速的定义 (8.33) (8.34)