INTRODUCTION VGK is a CFD (computational fluid dynamics) method coded in Fortran for predicting the aerodynamic characteristics of a 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@ but the code has been calibrated against experimental data to provide a method of estimating a separation boundary* ?C see Ref. 2 and Part 3. VGK was developed over a period of years at RAE/DERA (now QinetiQ@ Farnborough) and is made available by IHS ESDU under the terms of an agreement with QinetiQ. The disk containing the files relating to VGK also contains a ??library' of files of aerofoil coordinates ?C see Appendix A for the list of aerofoils provided. The Data Items dealing with VGK@ of which this is the second@ are: Part 1: Principles and results@ Part 2: User manual@ Part 3: Estimation of a separation boundary in transonic flow@ Part 4: Use of VGK to calculate excrescence drag at subsonic speeds@ Part 5: Design to a specified upper-surface pressure distribution@ Part 6: Aerofoil with simple hinged flaps@ Part 7: VGK for Windows TM. This Item describes the use of the variant of the VGK program suite that can be run in Microsoft Windows from a Command Window. 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. Typical computing time for a single run of VGK using a 80486 DX processor is 90 seconds and using a Pentium 90 processor is 30 seconds. The file name convention adopted for VGK runs is given in Section 2.1. A description of the various types of VGK run is given in Section 3. The functions of the files and the way they are used and produced by the programs VGKCON (the VGK ??control' program) and VGK are presented in Section 4. The specification of the file providing the coordinates of the aerofoil of interest is given in Section 5. Results of example VGK runs are given in Section 6. Section 7 contains a description of some of the problems that may be encountered with VGK runs and how they might be overcome. Detailed commands for using the programs are given in Section 8. The production of graphical output is dealt with briefly in Section 9. * VGK has been subsequently extended (as BVGK) to deal additionally with the effects of low Reynolds numbers and with boundary-layers with (small) regions of separation@ see Part 1@ Section 6.
ESDU 96029 C-2010 history
2010ESDU 96029 C-2010 Transonic data memorandum VGK method for two-dimensional aerofoil sections Part 2: User manual