large eddy simulation and proper orthogonal decomposition analysis of two-phase turbulent thermomagnetic convection of a ferrofluid in a cubic cavity

This paper presents the large-eddy-simulation (les) of two-phase turbulent thermo-magnetic convection of ferrofluid (water-fe3o4) within a cubic cavity. the current two-phase model considers brownian, thermophoresis, magnetophoresis, and eddy diffusions in the dispersion of ferromagnetic particles. two parallel electrical wires influence ferrofluid flow. the numerical computations are performed by utilizing the finite volume method for three different magnetic numbers (i.e. mnf=0, 1.4×1010 and 1.4×1010). for all numerical calculations, particle volume fraction and rayleigh are held constant at 0.04 and 108, respectively. based on the heat transfer analysis, a magnetic field with a strength of 5.6×1010 enhances the nusselt number by 16.67%. observed increases in heat transfer can probably be attributed to the kelvin force induced by the magnetic field, which affects the coherent structures of the flow. using the proper orthogonal decomposition (pod) method, coherent structures are extracted from velocity and pressure fluctuations. further, the time coefficients of the first three modes are extracted for the pressure fluctuation. according to the results, the applied magnetic field reduces the cumulative energy of modes and increases the number of modes required to reconstruct a given amount of flow. the coherent structures also change from plane to spanwise roll structures with increasing magnetic number. the energy content of the first three modes decreases from 98.7% to 73% as the magnetic field increases from mnf=0 to 1.4×1010.