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 see Ref. 2 and Part 3. VGK was developed over a period of years at RAE (now DERA@ Farnborough) and is made available by ESDU International plc under the terms of an agreement with DERA. Crown copyright is retained in the VGK source code. The disk containing the files relating to VGK also contains a ??library?? of files of aerofoil coordinatessee 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 for operation with MS-DOS and UNIX systems@ Part 3: Estimation of a separation boundary in transonic flow@ Part 4: Use of VGK to calculate excrescence drag magnification (to be issued)@ Part 5: User manual for ESDUview variant (to be issued). This Item describes the use of the variant of the VGK program suite that can be run with a computer utilising an operating system that is either MS-DOS or UNIX. It is necessary that a Fortran 77 compiler be available on the computer utilised. 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 with the UNIX operating system are given in Section 8@ and with the MS-DOS operating system in Section 9. The production of graphical output is dealt with briefly in Section 10. ??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 A-1997 history
1997ESDU 96029 A-1997 VGK METHOD FOR TWO-DIMENSIONAL AEROFOIL SECTIONS PART 2: USER MANUAL FOR OPERATION WITH MS-DOS AND UNIX SYSTEMS