a=2 b=1
A bullet is to be tested in the laboratory to determine the dragforce on it. Dependent parameter the drag force D (Newton) dependson the velocity of the bullet V(m/s), the length of the bulletL(m), sound velocity c(m/s), density of fluid Ï (kg/m3)and dynamic viscosity µ(kg/ms).
Solve the problem by making the necessary assumptions anddrawing the schematic figure
I-Determine the nondimensional p parameters using repeatingvariables
ii-a bullet with a speed of 9a,b m/s in air may be modelled in awater tunnel with a test section velocity of 2ab cm/s. Determinethe length of the model, if the length of the bullet is 5a,b mm.The air and water temperature is 20 oC degree at 1atm.
iii- if the drag force on the model is measured to be 2,ab N,then determine the expected drag force on the bullet. Comment ondynamic similarity equivalence?
