埋め込み境界－格子ボルツマン法による濡れ性の計算

抄録

We improve the accuracy and the numerical stability of the immersed boundary-lattice Boltzmann method (IB-LBM) to calculate the motion of a droplet on hydrophobic surfaces in complex geometry. To exactly derive the Chan-Hilliard equation, we use the proper source term proposed by Liang and the two-relaxation-time (TRT) collision operator. The series of the numerical tests, including Zalesak’s disk rotation, a single vortex, and a deformation of a sphere demonstrate that the computational effectiveness of the TRT collision operator is superior to that of the multi relaxation time collision operator. Analytical and numerical solutions of the symmetric shear flows demonstrate that the implicit diffuse direct-forcing method without the computational cost of the sparse matrix solver reduces the velocity slip and boundary value deviation as effectively as the implicit correction method for any relaxation times. The present IB-LBM with the TRT collision operator appropriately calculates the contact angle of liquids on the arbitrary shaped surfaces.