In an effort to answer the age-old question: What *is* the lift-coefficient of Iron Man? I have embarked upon the task of building a low-speed subsonic wind tunnel. As stated in the disclaimers below, the results obtained from testing models in this tunnel are unlikely to be very accurate, but the process should stil be fun. [citation-needed]
This site is, most certainly, meant to be informative to all those who also wish to build/understand low-speed subsonic wind tunnels. As I am still in the process of discovering this information, myself, the quality of the information presented is going to be sub-par until such time as I have both learned the material to my satisfaction, and also had opportuntity to present it in a reasonable manner -- please be patient.
For the purposes of determining bluff-body flow characteristics, the most important similarity paramter is the Reynolds Number. Unfortunately, any Reynolds number acheivable with my modest resources will be far too small to be of great interest. Consequently, any data derived from the finished product would have to be taken with a grain of salt (or, quite possibly, with a heaping bowl of salt....but hey, salt of the earth and all...or something).
The information contained herein is in reference to low-speed subsonic wind tunnels . When the Mach number is below ~0.3, it can be shown that the effects of compressibility are < 5%, allowing them to be virtually ignored. Consequently, calculations, decisions, and explanations contained within this page, all assume an incompressible fluid. [citation-needed]
Another important note of convention is that all references to 'before' and 'after' are in reference to the flow direction with the 'staring point' being the test-section. In future discourse, the subject will begin with the test-section and progress in the direction of flow.
Given that some notation will be required to properly convey the information contained herein, let us now define it: