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Unformatted text preview: 42 Physics Formulary by ir. J.C.A. Wevers Sr: (non-stationary inertial forces)/(stationary inertial forces) Fr: (stationary inertial forces)/(gravity) Fo: (heat conductance)/(non-stationary change in enthalpy) Pe: (convective heat transport)/(heat conductance) Ec: (viscous dissipation)/(convective heat transport) Ma: (velocity)/(speed of sound): objects moving faster than approximately Ma = 0,8 produce shock- waves which propagate with an angle with the velocity of the object. For this angle holds Ma = 1 / arctan( ) . Pr and Nu are related to specic materials. Now, the dimensionless Navier-Stokes equation becomes, with x = x/L , v = v/V , grad = L grad, 2 = L 2 2 and t = t : Sr v t + ( v ) v =- grad p + g Fr + 2 v Re 9.5 Tube fows For tube ows holds: they are laminar if Re < 2300 with dimension of length the diameter of the tube, and turbulent if Re is larger. For an incompressible laminar ow through a straight, circular tube holds for theturbulent if Re is larger....
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- Spring '10