Numerical Solutions Applied To Heat Transfer And Fluid Mechanics Problems
Steps in the finite difference solution of a problem
Determine the appropriate mathematical model for the problem.
Energy conservation equation
Boundary Conditions
At a surface of a conducting structure either the temperature or the heat flux is specified. A fixed temperature does not represent of any real physical configuration, but can be an appropriate approximation for a structure adjacent to a region with very high conductivity and total heat capacity. Surface heat flux within the structure is expressed in terms of the normal derivative of the temperature. Useful flux boundary conditions include:
Constant surface heat flux,
Adiabatic boundary condition,
Convection,
Convection and radiation
For problems with conduction through two regions with two different materials, fluxes must match at the boundary between the regions,
Initial Conditions
T(x, y, z, t=0) = f(x,y,z)
Example: Fluid Flow with Heat Transfer (2D - Steady State)
Conservation equations:Continuity
Momentum Equations (u is "x" component, v is "y" component)Energy Equation
Boundary Conditions
| Inlet | x = 0, | u = Uin, | v = 0, | T = Tin |
| Walls | y = b, | u = 0, | v = 0, | T = Tw |
| Symmetry | y = 0, |  |
v = 0, |  |
| Outlet | ? |
