Chapter 5 Incompressible Flow Finite Wings
Chapter 5 Incompressible Flow Finite Wings
5.1 Introduction o The properties of airfoils are the same as the properties of a wing with infinite span. However, all real airplanes have wings of finite span eIn the present chapter, we will apply our knowledge of airfoil properties to the analysis for finite wings o As We have mentioned in the previous chapter, the analysis for the aerodynamics of wings is separated in two steps. Now, we are going on the second step in Prandtl's philosophy of wing theory
5.1 Introduction The properties of airfoils are the same as the properties of a wing with infinite span. However, all real airplanes have wings of finite span. In the present chapter, we will apply our knowledge of airfoil properties to the analysis for finite wings. As we have mentioned in the previous chapter, the analysis for the aerodynamics of wings is separated in two steps. Now, we are going on the second step in Prandtl’s philosophy of wing theory
Streamline over the top surface Streamline over the bottom surface Top vie (planform) Wing area=S Wing span b
Ft Low pressure ront vIew High pressure
Question: why are the aerodynamic characteristics of a wing any different from the properties of its section? Airfoil can be respected as two-dimensional body, but any finite wing is a three-dimensional body ATtention should be paid for the flow pattern near the wing tips. And try to understand the reason for such a flow phenomena X For general cases, there is a spanwise velocity component on both top and bottom surface of the wing, but their direction are different XX A trailing vortex is created at each wing tip. These wing-tip vortices downstream of the wing induce a small downward velocity in the neighborhood of the wing itself
Question : why are the aerodynamic characteristics of a wing any different from the properties of its section? Airfoil can be respected as two-dimensional body, but any finite wing is a three-dimensional body. ※Attention should be paid for the flow pattern near the wing tips. And try to understand the reason for such a flow phenomena. ※ For general cases, there is a spanwise velocity component on both top and bottom surface of the wing, but their direction are different. ※ A trailing vortex is created at each wing tip. These wing-tip vortices downstream of the wing induce a small downward velocity in the neighborhood of the wing itself