Development of an efficient large time step unsteady solver for incompressible flows using the IDEAL algorithm in OpenFOAM

Numerical simulation of engineering applications usually has a relatively low requirement for time resolution but a high requirement for computational efficiency. In order to efficiently simulate the unsteady engineering problems, a large time step unsteady solver for incompressible flows is developed based on the most popular open-source CFD software - OpenFOAM. In this solver, the coupling between velocity and pressure is solved using the IDEAL algorithm, which was first proposed by the present author. Then, two test cases are performed to verify the performance superiority of the developed solver. The results indicate that the IDEAL algorithm can converge to the steady-state solution at a much larger time step. Compared with the PISO and PIMPLE algorithms, the IDEAL algorithm can save the computational time by 34.9–88.8% and 19.8–94.1%, respectively. The developed solver has all the advantages of OpenFOAM software, which has a significant benefit in simulating the unsteady incompressible flows of engineering applications.