Copyright by Dr.Zheyan Jin Chapter 3 Fundamentals of Inviscid,Incompressible Flow 3.2 Pressure Coefficient Pressure,by itself,is a dimensional quantity.The pressure coefficient is defined as: C。=P-p2 1 where qoo For incompressible flows,Cp can be expressed in terms of velocity only Consider the flow over an aerodynamics body immersed in a freestream with pressure p and velocity VPick an arbitrary point in the flow where the pressure and velocity are p and V,respectively.From Bernoulli's equation P.+V:-P+V:OF P-P.-0 (V-PV) 2p-2 The pressure coefficient: 1 Copyright by Dr. Zheyan Jin Chapter 3 Fundamentals of Chapter 3 Fundamentals of Inviscid Inviscid, Incompressible Flow , Incompressible Flow 3.2 Pressure Coefficient For incompressible flows, Cp can be expressed in terms of velocity only. Consider the flow over an aerodynamics body immersed in a freestream with pressure p ͚and velocity V͚. Pick an arbitrary point in the flow where the pressure and velocity are p and V, respectively. From Bernoulli’s equation where 2 2 1    V q      q p p Cp 2 2 （ V 2 V 2 ） 2 1 V or 2 1 V 2 1 p      p   p  p       The pressure coefficient: Pressure, by itself, is a dimensional quantity. The pressure coefficient is defined as: 2 2 2 2 1 V 2 1 ( ) 2 1                    V V V V q p p Cp  