Last Updated: 9/9/07
Excel/VBA
Spreadsheets for 1-D, Compressible Flow of an Ideal Gas
1.
1-D Isentropic with Area Change, Normal
Shocks, Fanno and Rayleigh Flows
2. Oblique, Planar Shocks
If you
click on the either of the titles below, a Microsoft Excel workbook will be
downloaded to your computer. These workbooks use modules written in Visual
Basic for Applications (VBA), Excel's macro language. They were written under
Windows, but should work under MS Office running on a Macintosh. Earlier
versions of MS Office on both platforms may not support all features used in
this workbook.
Disclaimer
No
warranties, expressed or implied, are made that these programs are free from
error, or are consistent with any particular standard of merchantability, or
will meet your requirements for any particular application. These programs
should not be relied on for solving problems whose incorrect solution could
result in injury or lost property. If you use these programs in such a manner,
it is at own risk. The author disclaims all liability for direct or
consequential damages resulting from your use of these programs, i.e., SOFTWARE
THAT IS FREE HAS NO GUARANTEE!
These
Excel workbook contains macros written in Visual Basic for Applications, so
that when you open them you will probably see a warning like, "[filename]
contains macros. Macros may contain viruses. It is always safe to disable
macros, but if the macros are legitimate, you might lose some
functionality." Then you are given the choices: "Disable
Macros", "Enable Macros" and "More Info". In the case
of these two spreadsheets, you must select "Enable Macros" or they
will not work at all! (If you not even offered this choice, then your security
is probably set at "High." You must have your security level in Excel
set at "Medium," which allows you to "choose whether or not to
run potentially unsafe macros.") My virus checker is set to update
automatically every day (yours should be too!). You might scan these materials
(and anything else containing macros you might download from the Internet)
before opening them, but then you MUST enable macros!
Compressible
Flow of an Ideal Gas (Updated: 9/10/07)
This
workbook implements the 1-D, compressible flow functions for a perfect
gas. The four worksheets include:
1. Isentropic flow (with area change), 
2. Normal shocks,
3. Fanno Line flow (adiabatic flow at
constant area with friction)
4. Rayleigh Line flow (stagnation
temperature change in the absence of friction and area change).
User
inputs are the Mach number and the ratio of specific heats. Results are returned in both
tabular and graphical form, as seen in the figure to the right. With the slider provided the user can
test the effect of different specific heat ratio immediately. A user form allows
the user to input derived quantities, e.g., the Mach number downstream of a
normal shock and have the program find the upstream Mach number. While results
are returned in tabular and graphical form on the four sheets included in the
Compressible.xls workbook, it is expected that the user will invoke any of the
16 VBA functions provided here in his or her own Excel calculations on a new
worksheet.
Oblique
Planar Shocks
(New: 1/2/07)
This
spreadsheet will compute two-dimensional, oblique shocks. The user must be willing to learn
Excel’s Solver Add-in in order to use it! It is set so that the user can easily input
the upstream Mach number and turn angle.
Using the Solver constraints the user
can solve
for either the strong (M2 <1) or weak (M2 >1) solution.
