# How to create a convective boundary condition in HEAT solver

#1

There are a few different options available in the Heat Transport Solver when it comes to defining a convective boundary condition to your simulation region.

1. Using the ‘Boundary Conditions’ option: Users can create a ‘thermal boundary’ and choose “convection” as the boundary model to define a convective boundary condition. Using this option users can define a constant value for the convection heat transfer coeficient, h.

2. Using (thermal) Fluids: Users can place a ‘Fluid’ type material in their simulation region (such as Air) and specify a convective boundary condition at the interfaces between the fluid and other materials using the ‘Material Interfaces’.

Under the ‘Thermal’ tab in the material interface, the users have the option to define a convective boundary condition besides heat flux and radiative boundary conditions. As shown on the screenshot above, the users have 5 different models available for the convective boundary condition, (i) constant h, (ii) natural convection (vertical plate), (iii) natural convection (top of horizontal plate), (iv) natural convection (bottom of horizontal plate), and (iv) forced convection. Apart from the first option, all other cases use the thermal properties of the Fluid to calculate the convection heat transfer coefficient using analytic models.