Rayleigh Number Calculator
Posted by Dinesh onOnline Rayleigh formula calculator to calculate rayleigh number for Fluid problems.
The Rayleigh number (Ra) for a fluid is a dimensionless number associated with buoyancy-driven flow, also known as free convection or natural convection.
When the Rayleigh number is below a critical value for that fluid, heat transfer is primarily in the form of conduction; when it exceeds the critical value, heat transfer is primarily in the form of convection.
Rayleigh Number Calculation
Formula:
where,
| g is acceleration due to gravity |
| β is the thermal expansion coefficient (equals to 1/T, for ideal gases, where T is absolute temperature). |
| ν is the kinematic viscosity |
| α is the thermal diffusivity |
| Ts is the surface temperature |
| T∞ is the quiescent temperature (fluid temperature far from the surface of the object) |
| x is the characteristic length |
| Rax is the Rayleigh number for characteristic length x |