A Viscous/potential Flow Interaction Analysis Method for Multi-element Infinite Swept Wings, Volume 1An analysis method and computer program have been developed for the calculation of the viscosity dependent aerodynamic characteristics of multi-element infinite swept wings in incompressible flow. The wing configuration consisting at the most of a slat, a main element and double slotted flap is represented in the method by a large number of panels. The inviscid pressure distribution about a given configuration in the normal chord direction is determined using a two dimensional potential flow program employing a vortex lattice technique. The boundary layer development over each individual element of the high lift configuration is determined using either integral or finite difference boundary layer techniques. A source distribution is then determined as a function of the calculated boundary layer displacement thickness and pressure distributions. This source distribution is included in the second calculation of the potential flow about the configuration. Once the solution has converged (usually after 2-5 iterations between the potential flow and boundary layer calculations) lift, drag, and pitching moments can be determined as functions of Reynolds number. |
Contents
LIST OF SYMBOLS | 8 |
BOUNDARY LAYER CALCULATION METHODS | 22 |
CALCULATION PROCEDURE | 37 |
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Common terms and phrases
1+ky boundary condition boundary layer calculation boundary layer development boundary layer method calculated pressure calculation procedure COMPARISON OF MEASURED cross flow Cumpsty and Head determined difference boundary layer dimensional displacement thickness double slotted flap eddy viscosity effects equations factor H finite difference boundary finite difference method flap surface flap upper surface geometry H₁ incompressible flow infinite swept wing initial inviscid iteration Kutta condition laminar boundary layer laminar flow leading edge leading edge slot lift coefficient Lockheed program lower surfaces MEASURED AND PREDICTED MULTI-ELEMENT INFINITE SWEPT NACA 23012 Airfoil NASA normal chord normal velocity OVERLAY panel parameter pitching moment potential core potential flow PREDICTED PRESSURE DISTRIBUTIONS pressure coefficients pressure gradient Reynolds number shape factor shear stress shown in Figure skin friction coefficient slat source distribution source strength spanwise stagnation line trailing edge transition turbulent boundary layer velocity profiles viscous/potential flow interaction vortex distribution vortices ду