Respuesta :
Answer:
The speed range is between 100 and 450 mph (not possible)
Explanation:
Given data:
Maximum characteristic length = 20 ft
Low speed = 20 mph
High speed = 90 mph
Maximum characteristic length of the model = 4 ft
Question: Determine the range of air velocities that would be required for the wind, VMT = ?
Are the velocities suitable?
It is desired that Reynolds's number be equal
Re = (Re)MT
Here MT is model test
[tex]\frac{\rho VL}{\mu } =(\frac{\rho _{MT} V_{MT} L_{MT} }{\mu _{MT} } )_{MT}[/tex]
[tex]v=\frac{\mu }{\rho }[/tex]
[tex]\mu =v*\rho[/tex]
Substituting
[tex]\frac{VL}{v } =\frac{V_{MT} L_{MT} }{v _{MT} }[/tex]
[tex]\frac{V_{MT} }{V } =\frac{L }{L_{MT} }[/tex]
[tex]\frac{V_{MT} }{V } =\frac{20}{4} =5[/tex]
[tex]V_{MT} =5V[/tex]
Velocity at slow speed:
[tex]V_{MT} =5*20=100mph[/tex]
Velocity at high speed
[tex]V_{MT} =5*90=450mph[/tex]
The speed range is between 100 and 450 mph (not possible)
