Significance:
- Used in fluid flow calculations where local pressure drop is necessary (dp = upstream pressure - downstream pressure)
- Used to characterize the losses in the flow.
- NEu = 1 corresponds to a perfect frictionless fluid flow.
=========================================================================
Significance:
- It gives the possibility / potential of a fluid to cavitate.
- If Ca < 0, Cavitation occurs & if Ca > 0 no cavitation will occur, since the condition to avoid cavitation is that the minimum pressure (Pmin)within the entire pump should be greater than the vapor pressure (Pv) of the fluid at that temperature. (Pmin > Pv )
=======================================================================
Significance:
- It is the ratio of mean flow velocity to the speed of small gravity wave along the water surface.
- It is an indication of resistance to partially submerged object moving through to water.
- Greater Fr value, greater is the resistance to flow.
- Fr < 1 indicates subcritical flow (tranquil flow)
- Fr > 1 indicates supercritical flow (rapid flow)
- Fr = 1 indicates critical flow.
- Used in ship design i.e. to analyze water flow around ships.
- Inverse of the square of Fr is called Richardson Number ( importance of natural convection to forced convection)
=======================================================================
Significance:
- To check whether the fluid can be considered compressible or not.
- If M < 0.2-0.3, then the fluid medium can be considered steady & isothermal & hence incompressible.
- Used for fluids flowing with high speeds in channels, nozzles, diffusers etc.
- It is analogous to Froude Number
C = speed of sound = 345m/s (at 15 deg. celsius temperature)
========================================================================
Significance:
- It is the square of mach number (Mach number can also be expressed in terms of bulk modulus as the square root of cauchy number number).
- Used to study compressible flow.
K = bulk modulus of elasticity
========================================================================
Significance:
- Used to study fluid friction in pipes.
Tw = wall stress
ef = friction loss
ef = friction loss
=========================================================================
