COMADI - Handbuch 1998

Abstract

In numerical simulations of flow phenomena enormous quantities of data have to be dealt with. Coordinates of calculation grids and flow parameters calculated at these points are stored in files. Depending on the model of calculation, the data includes velocity components or parameters defining temperature , pressure or turbulence. Special programs are needed to evaluate and process the data for representation. These programs are called "post-processing programs" and their function is to graphically display results easily recognizable even to the unskilled users eye. Common objects of representation are velocity vectors, iso-surfaces, i.e. surfaces of constant flow parameters, or the distribution of a flow quantity over an area. These requirements were to be met when designing the Comadi program. Comadi was developed at the Institut für Strömungsmechanik of Deutsches Zentrum für Luft- und Raumfahrt (DLR). It is an interactive and programmable system of computational methods used for collecting, generating and displaying various kinds of data (Data Compile Make and Display). Any chosen geometric shape can be displayed and given the special position that suits the users purpose best. Functions are supplied that enable the user to modify and to extend the given data set. A choice of color maps is provided with which a vivid and informative representation can be achieved. This manual was composed in the course of a study carried out by Ruhrgas in cooperation with the Deutsches Zentrum für Luft- und Raumfahrt (DLR), and is designed to give an introduction to the various possibilities offered by the Comadi program. Rather than an exhaustive documentation it should be considered an introductory guide for self-teaching and practising applications of the program. A careful study of this manual will prepare the user to find the best possible solution to his problems with the help of the Comadi program. This manual is divided into two main parts, each subdivided into further sections. Part one gives an introduction to the program, with the structure of Comadi described and the most frequently applied menus explained in detail. Part two gives examples, demonstrating in particular the representation of often recurring picture details. The appendix gives information of interest for the user, such as lists of file formats, fonts, etc. supported by Comadi.