for a rotating cylinder evaluated by Eq. (5) are depicted as functions of rotation rate. When Re 00 >Re c2 , normal force (or drag) coefficient C N increases monotonically as the Reynolds number increases. (Figure 3 shows the case for V QO = 30 m/s.) This will explain why the drag force on a rotating body in the drop test is greater than that on the model at rest in the wind tunnel test. 2 In view of the rough approximate analysis, qualitative agreement with the experimental data is encouraging as a method to predict the maximum rotation rates near critical Reynolds number.From the practical point of view, the flat spin will be prevented by making the boundary layer on the whole surface of the body turbulent with artificial roughness elements such as tripping wires. 10
NomenclatureC, = rolling moment/g^ Sd, rolling moment coefficient C lp = 3C,/d (pd/2 V^), roll damping coefficient d = body diameter M^ = freestream Mach number p -roll rate, rad/s q^ = freestream dynamic pressure Re d = Reynolds number based on body diameter S = ird 2 /4, reference area V^ = freestream velocity
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.