A decoupled wavelet approach for multiple physical flow fields of binary nanofluid in double-diffusive convection

Abstract

The paper aims at applications of a decoupled wavelet method for investigating multiple physical steady flow fields of binary nanofluids in double-diffusive mixed convection. The Buongiorno’s mathematical model of nanofluids is further perfected in the presence of Dufour and Soret effects, incorporating with linear and nonlinear diffusiophoresis effects based on experiments [Chemical Engineering Science 176 (2018): 632–640]. Nonhomogeneous thermal boundaries corresponding to heat flux on vertical walls and convection heat transfer at the bottom along with moving top lid are effectively approximated by interpolated Coiflet-type wavelet. Highly coupled and nonlinear governing equations for the complex fields of temperature, nanoparticles volume fraction and solute concentration have been formulated and decomposed into linear differential ones by homotopy transformation. Numerical wavelet solutions with larger range of physical parameters are finally obtained and validated by solving a set of iterative algebra equations applying Galerkin method, which are difficult to be given by traditional numerical methods. The results reveal that nanoparticles and double-diffusive buoyancy parameters, the thermo-nanofluid and thermo-solutal Lewis numbers, the heat conductivity coefficient, the periodical heat flux with different phase differences, the diffusiophoresis parameters, the nanoparticles and solute Dufour parameters, the solute Soret parameter are of great significance on characteristics of heat and mass transfer in the complex flow.