Abstract:

This is the second in a sequence of Data Items to accompany the VGK method for two-dimensional aerofoil sections. VGK is a CFD (computational fluid dynamics) method coded in Fortran for predicting the aerodynamic characteristics of a two-dimensional single element aerofoil in a subsonic freestream, including the effects of viscosity (boundary layers and wake) and shock waves. VGK uses an iterative approach to solve coupled finite-difference equations for the inviscid flow region (assumed to be potential) and the viscous flow region (represented by integral equations). The aerofoil boundary-layers must be attached for VGK to produce results that correspond to the real flow. VGK was developed over a period of years at RAE/DERA (now QinetiQ, Farnborough) and is made available by ESDU under the terms of an agreement with QinetiQ.

Sufficient information is given in this Item to obtain results from VGK, but Part 1 should be referred to for the principles and performance of the method, so that the results obtained may be properly assessed.

A 'library' of files containing aerofoil coordinates is also supplied.

Because of its good performance, VGK can be utilised effectively to investigate a number of factors, such as: The influence of aerofoil geometry (profile and camber) changes on aerofoil characteristics at and around cruise conditions. The influence of changes in Mach number, Reynolds number and transition locations on aerofoil characteristics. The influence of deflection through small angles of leading- and/or trailing edge flaps. The influence of over-fixing transition in wind-tunnel tests on aerofoils.

See also:

• ESDU 96028: VGK method for two-dimensional aerofoil sections. Part 1: Principles and results
• ESDU 97030: VGK method for two-dimensional aerofoil sections. Part 3: estimation of a separation boundary in transonic flow
• ESDU 98031: VGK method for two-dimensional aerofoil sections. Part 4: estimation of excrescence drag at subsonic speeds
• ESDU 99032: VGK method for two-dimensional aerofoil sections. Part 5: design to a specified upper-surface pressure distribution
• ESDU 01033: VGK method for two-dimensional aerofoil sections. Part 6: aerofoil with simple hinged flaps