Estimation for viscoelastic fluid flow behind a cylinder using data assimilation

Abstract

Each experiment and numerical simulation in fluid flow analysis has advantages and disadvantages. In the numerical simulation of non-Newtonian fluids such as a viscoelastic fluid, although detailed flow information can be obtained, the relationship between fluid additive concentration and the dimensionless number of viscoelastic parameters is not necessarily known. In order to estimate the actual stress and/or pressure fields affected by fluid elasticity, a promising method would be data assimilation, which is a simulation with successive corrections by measurement data. In this study, we have estimated the flow fields of a cylinder wake confined in a channel for a surfactant solution and a viscoelastic fluid based on Giesekus model, in the framework of data assimilation. The viscoelastic force given by the Giesekus model and the body force estimated by data assimilation reveals a good agreement in the high shear region.