Editing Drag equation (section)

==Experimental methods==
{{unreferenced section|date=January 2022}}
To empirically determine the Reynolds number dependence, instead of experimenting on a large body with fast-flowing fluids (such as real-size airplanes in [[wind tunnel]]s), one may just as well experiment using a small model in a flow of higher velocity because these two systems deliver [[Similitude (model)|similitude]] by having the same Reynolds number. If the same Reynolds number and Mach number cannot be achieved just by using a flow of higher velocity it may be advantageous to use a fluid of greater density or lower viscosity.<ref name="Zohuri2015">{{cite book |last=Zohuri |first=Bahman |title=Dimensional Analysis and Self-Similarity Methods for Engineers and Scientists |year=2015 |publisher=Springer, Cham |doi=10.1007/978-3-319-13476-5_2 |chapter=Similitude Theory and Applications|pages=93–193 |isbn=978-3-319-13475-8 }}</ref>