Excel Add-ins for Gas Dynamics Courses

Abstract

EXCEL ADD-IN FOR GAS DYANAMICS COURSESTraditional Gas Dynamics courses rely on graphical or tabulated data for computation of isentropic flows,normal and oblique shocks, expansion waves, flows with friction, and flows with heat transfer. Also,most current text books refer students to spreadsheets or mathematical calculation programs such asMathCad or Maple to program the appropriate formulas. These programs work well, but often require thestudent to program the functions themselves. While possibly a useful exercise, programing the functionsis prone to errors and can be time consuming.Microsoft Excel is literally on almost every computer in the world. A recent survey of alumni of theauthors’ institution revealed that only a few used the analysis software that we use to teach, such asANSYS, Matlab, and, Mathcad in his or her daily practice. Almost no one used specialty software thatwas packaged with textbooks. However, almost every one used Excel on a daily basis. Modern versionsof spreadsheets such as Excel come with many built-in engineering functions and have powerfulprograming adjuncts such as Visual Basic for Applications (VBA). With this in mind, the authors andtheir colleagues and students have developed a suit of add-ins for Excel that turn many mechanicalengineering thermal-science computations into Excel function calls. The goal of this work is to providestudents, teachers, and practicing engineers with a useful wide-ranging tool kit.This paper discusses the development of an Excel add-in tool kit for basic gas dynamics. The tool kitincludes functions for isentropic flow, normal and oblique shocks, expansion waves, flow with friction—Fanno flow, and flow with heat transfer—Rayleigh flow. The scope and availability of the tool kit arediscussed, and examples are provided. The tool kit has been used for two classes of advancedundergraduate/beginning graduate student sections of gas dynamics in a mechanical engineering program.Classroom experiences and student viewpoints are discussed.