Course No Course Title Credits

dynamic similitude between different experimental cases. They are also used
to characterize different flow regimes, such as laminar or turbulent flow:
laminar flow occurs at low Reynolds numbers, where viscous forces are
dominant, and is characterized by smooth, constant fluid motion, while
turbulent flow occurs at high Reynolds numbers and is dominated by inertial
forces, which tend to produce chaotic eddies, vortices and other flow
instabilities.
Grashof number Gr
The Grashof number Gr is a dimensionless number in fluid dynamics
and heat transfer which approximates the ratio of the buoyancy to viscous
force acting on a fluid. It frequently arises in the study of situations involving
natural convection. It is named after the German engineer Franz Grashof.
Gr
L
3
g β(
T −T∞
) L
= for vertical flat plates
s
2
υ
Gr
L
3
g β(
T −T∞
) D
= for pipes
s
2
υ
where the L and D subscripts indicates the length scale basis for the Grashof
Number.
g = acceleration due to Earth's gravity
β = volumetric thermal expansion coefficient
(equal to approximately 1/T, for ideal fluids, where T is absolute
temperature)
T s = surface temperature
T ∞ = bulk temperature
L = length
D = diameter
υ = kinematic viscosity