Fellow engineers,
I'm working through some practice exams (specifically the Lindeburg Practice Exam) and running into some extremely frustrating issues with assumptions at times. This latest issue is about the morning session's #28.
There are several ways of finding the coefficient of drag on an object in a fluid stream, but the solution here finds the Reynolds #, and the L/h ratio, and uses them to find the coefficient of drag "graphically." Ok... Where's that graph? It's not in the Lindeburg MERM. And what's up with needing to estimate a coefficient of drag, and having answers that are nearly within 10% of each other?!
Depending on what online reference you would like to choose, you could have the coefficient of drag differing from their assumption by almost 100%! And keep in mind, the problem gave no description of shape other than its length, width, and height. I would assume it was a rectangular prism, but then I'd miss the problem.
What do you guys use to estimate the coefficient of drag on an object moving through air?
Thanks for any help!
I'm working through some practice exams (specifically the Lindeburg Practice Exam) and running into some extremely frustrating issues with assumptions at times. This latest issue is about the morning session's #28.
There are several ways of finding the coefficient of drag on an object in a fluid stream, but the solution here finds the Reynolds #, and the L/h ratio, and uses them to find the coefficient of drag "graphically." Ok... Where's that graph? It's not in the Lindeburg MERM. And what's up with needing to estimate a coefficient of drag, and having answers that are nearly within 10% of each other?!
Depending on what online reference you would like to choose, you could have the coefficient of drag differing from their assumption by almost 100%! And keep in mind, the problem gave no description of shape other than its length, width, and height. I would assume it was a rectangular prism, but then I'd miss the problem.
What do you guys use to estimate the coefficient of drag on an object moving through air?
Thanks for any help!