Eventos Anais de eventos
ENCIT 2022
19th Brazilian Congress of Thermal Sciences and Engineering
VALIDATION OF IMERSPEC2D USING GREEN-TAYLOR VORTICES AND TEMPORAL JET
Submission Author:
Thiago Fernando Santiago de Freitas , MG , Brazil
Co-Authors:
Thiago Fernando Santiago de Freitas, Aristeu Silveira Neto, Felipe Pamplona Mariano
Presenter: Thiago Fernando Santiago de Freitas
doi://10.26678/ABCM.ENCIT2022.CIT22-0247
Abstract
The present paper shows the simulations of Taylor-Green vortices and temporal jet using the IMERSPEC2D algorithm. The Taylor-Green vortices are simulated to compare the computational solution obtained by the IMERSPEC2D to a manufactured solution, in order to verify the computational code. Jets are frequently found in nature or in industrial applications such as component mixing processes, thermal transfer, lubrication and deicing, fuel injection in combustion chambers and aircraft propulsion systems, therefore the computational simulations can help in the comprehension and/or evolution of the flow formulation. The IMERSPEC2D solves the continuity equation and linear momentum equations numerically implementing the Pseudo-Spectral Fourier Method (PFM) with the use of the Discrete Fourier transform (DFT) and the Immersed Boundary Method (IBM). This approach permits performing computational simulations in regular orthogonal uniform meshes and achieving machine error with relatively low computational cost when compared to other spectral methodologies. The reduced computational cost is achieved by the use of DFT as well as the pseudo-spectral approach which does not solve the convolution product of the advective term found in momentum linear equations. Furthermore, the mathematical process of pressure projection replaces the solution of Poisson Equation to vector-matrix multiplication, ensuring the mass balance. The Taylor-Green vortices simulations results show the machine error (errors with 10E(-15) magnitude) with and without the use of IBM while the temporal jet simulations results show good agreement of the 2D simulations and the 3D until the three-dimensionalization of the flow. The formation of eddies is presented for flows with different levels of perturbation in the inlet boundary conditions. The use of different levels of perturbations in the initial condition flow to model temporal jet in transition to turbulence was discovered as a necessity since the high accuracy of the spectral approach. Without inserting small perturbations, the flow does not transition to turbulence neither generate the expected turbulent structures in the flow.
Keywords
Green-Taylor Vortices, Jet flow, Immersed Boundary Method, Pseudo-spectral method
