Simulation Example - Natural Convection in a Square Cavity


Natural convection is a phenomenon in which the fluid motion is driven by buoyancy forces, caused by density differences due to temperature variations in the fluid. Natural, or free, convection of an air mass can be observed, for example, in a coastal region during a summer day when the sun heats up the land and the water. Water takes longer to warm up than land. As a result, the air above the land heats up faster, becomes less dense and rises under the buoyancy force. It is then replaced by the cooler and denser air from the sea, thus resulting in the circular air motion pattern producing a sea breeze.

In this example, we explore the natural convection of air in a square cavity with two vertical walls maintained at different temperatures. This temperature difference causes the circular motion of air inside the cavity due to buoyancy forces.


The main objective of this example is to understand and visualize the process of natural convection in a square cavity using Ansys Fluent simulation.


Download the Mesh file required for setting up the simulation and associated Case and Data files from here. Follow the instructions below to set up this simulation in Ansys Fluent starting with the mesh file. In case you face any issues setting up or running the simulation, refer to corresponding initial and final Case and Data files.

Alternate video link.

Results and Discussion

Let’s us now analyze the simulation results and understand the physics of natural convection.