Rayleigh Number Calculator

✖Grashof number approximates the ratio of the buoyancy to viscous force acting on a fluid.ⓘ Grashof Number [G]			+10% -10%
✖Prandtl number (Pr) or Prandtl group is a dimensionless number, named after the German physicist Ludwig Prandtl, defined as the ratio of momentum diffusivity to thermal diffusivity.ⓘ Prandtl Number [Pr]			+10% -10%

✖Rayleigh number is a dimensionless parameter that is a measure of the instability of a layer of fluid due to differences of temperature and density at the top and bottom.ⓘ Rayleigh Number [Ra]

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Formula

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Rayleigh Number

Formula

`"Ra" = "G"*"Pr"`

Example

`"0.35"="0.5"*"0.7"`

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Rayleigh Number Solution

STEP 0: Pre-Calculation Summary

Formula Used

Rayleigh Number = Grashof Number*Prandtl Number
Ra = G*Pr
This formula uses 3 Variables

Variables Used

Rayleigh Number - Rayleigh number is a dimensionless parameter that is a measure of the instability of a layer of fluid due to differences of temperature and density at the top and bottom.
Grashof Number - Grashof number approximates the ratio of the buoyancy to viscous force acting on a fluid.
Prandtl Number - Prandtl number (Pr) or Prandtl group is a dimensionless number, named after the German physicist Ludwig Prandtl, defined as the ratio of momentum diffusivity to thermal diffusivity.

STEP 1: Convert Input(s) to Base Unit

Grashof Number: 0.5 --> No Conversion Required
Prandtl Number: 0.7 --> No Conversion Required

STEP 2: Evaluate Formula

Substituting Input Values in Formula

Ra = G*Pr --> 0.5*0.7

Evaluating ... ...

Ra = 0.35

STEP 3: Convert Result to Output's Unit

0.35 --> No Conversion Required

FINAL ANSWER

0.35 <-- Rayleigh Number

(Calculation completed in 00.004 seconds)

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Created by Nishan Poojary

Shri Madhwa Vadiraja Institute of Technology and Management (SMVITM), Udupi

Nishan Poojary has created this Calculator and 500+ more calculators!

Verified by Rajat Vishwakarma

University Institute of Technology RGPV (UIT - RGPV), Bhopal

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< 20 Dimensionless groups Calculators

Bingham Number

Go Bingham Number = (Shear Yield Strength*Characteristic Length)/(Absolute Viscosity*Velocity)

Viscous force given grashofs number

Go Viscous Force = sqrt((Buoyant Force*Inertia Force)/Grashof Number)

Eckert Number

Go Eckert Number = (Flow Velocity)^2/(Specific Heat Capacity*Temperature Difference)

Stanton number given Nusselt number and other dimensionless groups

Go Stanton Number = Nusselt Number/(Reynolds Number*Prandtl Number)

Nusselt number given Stanton number and other dimensionless groups

Go Nusselt Number = Stanton Number*Reynolds Number*Prandtl Number

Buoyant force given grashof number

Go Buoyant Force = Grashof Number*(Viscous Force^2)/Inertia Force

Internal conduction resistance given biot number

Go Internal Conduction Resistance = Biot Number*Surface Convection Resistance

Surface convection resistance

Go Surface Convection Resistance = Internal Conduction Resistance/Biot Number

Stanton number for convection

Go Stanton Number = Wall heat transfer rate/Heat Transfer by Convection

Modified Rayleigh number given Bingham number

Go Modified Rayleigh Number = Rayleigh Number/(1+Bingham Number)

Heat diffusivity given Lewis number

Go Heat Diffusivity = Lewis Number*Mass Diffusivity

Rayleigh Number

Go Rayleigh Number = Grashof Number*Prandtl Number

Reynolds number given Peclet number

Go Reynolds Number = Peclet Number/Prandtl Number

Prandtl number given Peclet number

Go Prandtl Number = Peclet Number/Reynolds Number

Reynolds number given Inertia and Viscous Force

Go Reynolds Number = Inertia Force/Viscous Force

Viscous force given Reynolds number

Go Viscous Force = Inertia Force/Reynolds Number

Pressure force given Euler number

Go Pressure Force = Euler Number*Inertia Force

Gravity force given Froude number

Go Gravity Force = Inertia Force/Froude Number

Froude Number

Go Froude Number = Inertia Force/Gravity Force

Euler Number

Go Euler Number = Pressure Force/Inertia Force

< 11 Dimensionless Numbers Calculators

Archimedes Number

Go Archimedes Number = ([g]*Characteristic Length^(3)*Density of Fluid*(Density of Body-Density of Fluid))/(Dynamic Viscosity)^(2)

Sommerfeld Number

Go Sommerfeld Number = ((Radius of Shaft/Radial Clearance)^(2))*(Absolute Viscosity*Speed of Rotating Shaft)/(Load per Unit of Area)

Reynolds Number

Go Reynolds Number = (Density of Liquid*Fluid Velocity*Pipe Diameter)/Dynamic Viscosity

Euler Number using Fluid Velocity

Go Euler Number = Fluid Velocity/(sqrt(Change in Pressure/Density of Fluid))

Weber Number

Go Weber Number = ((Density*(Velocity of Fluid^2)*Length)/Surface Tension)

Eckert Number

Go Eckert Number = (Flow Velocity)^2/(Specific Heat Capacity*Temperature Difference)

Grashof Number

Go Grashof Number = (Buoyant Force)/(Viscous Force)

Rayleigh Number

Go Rayleigh Number = Grashof Number*Prandtl Number

Mach Number

Go Mach Number = Speed of Object/Speed of Sound

Froude Number

Go Froude Number = Inertia Force/Gravity Force

Euler Number

Go Euler Number = Pressure Force/Inertia Force

Rayleigh Number Formula

Rayleigh Number = Grashof Number*Prandtl Number
Ra = G*Pr

What is Convection?

Convection is the process of heat transfer by the bulk movement of molecules within fluids such as gases and liquids. The initial heat transfer between the object and the fluid takes place through conduction, but the bulk heat transfer happens due to the motion of the fluid.

How to Calculate Rayleigh Number?

Rayleigh Number calculator uses Rayleigh Number = Grashof Number*Prandtl Number to calculate the Rayleigh Number, The Rayleigh Number formula is defined as a dimensionless parameter that is a measure of the instability of a layer of fluid due to differences of temperature and density at the top and bottom. Rayleigh Number is denoted by Ra symbol.

How to calculate Rayleigh Number using this online calculator? To use this online calculator for Rayleigh Number, enter Grashof Number (G) & Prandtl Number (Pr) and hit the calculate button. Here is how the Rayleigh Number calculation can be explained with given input values -> 0.35 = 0.5*0.7.

FAQ

What is Rayleigh Number?

The Rayleigh Number formula is defined as a dimensionless parameter that is a measure of the instability of a layer of fluid due to differences of temperature and density at the top and bottom and is represented as Ra = G*Pr or Rayleigh Number = Grashof Number*Prandtl Number. Grashof number approximates the ratio of the buoyancy to viscous force acting on a fluid & Prandtl number (Pr) or Prandtl group is a dimensionless number, named after the German physicist Ludwig Prandtl, defined as the ratio of momentum diffusivity to thermal diffusivity.

How to calculate Rayleigh Number?

The Rayleigh Number formula is defined as a dimensionless parameter that is a measure of the instability of a layer of fluid due to differences of temperature and density at the top and bottom is calculated using Rayleigh Number = Grashof Number*Prandtl Number. To calculate Rayleigh Number, you need Grashof Number (G) & Prandtl Number (Pr). With our tool, you need to enter the respective value for Grashof Number & Prandtl Number and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.

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