Secondary flows are relatively minor flows that occur in real viscous flows and are superimposed on the primary flow. They are the result of crossflow pressure gradients that may arise depending on flow conditions and domain shape. For example, secondary flows are formed on aircraft swept-back wings, turbomachinery blades and propellers due to the presence of crossflow pressure gradients and streamline curvature. Secondary flows also develop in internal flows through bent or curved ducts, for example an S-shaped duct. Such ducts are commonly found in HVAC systems and other industrial applications. In this simulation we will analyze the flow through an S-Duct and observe the formation of secondary flows inside the duct.
The main objective of this example is to understand and visualize the primary and secondary flows in the S-bend duct using Ansys Fluent simulation. You will also learn the concept of the pressure recovery coefficient to measure total losses in the duct.
Download the Mesh file required for setting up the simulation and associated Case & Data files 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, please refer to the corresponding initial and final Case and Data files.
Let us now analyze the simulation results and understand the physics of laminar flow inside an S-bend.