Reduction of Numerical Dispersion in Multiquardrics Radial Basis Collocation Method in Solute Transport Simulation

Abstract

Solute transport in porous medium can be described by the mathematical model of advection-dispersion equation (ADE) When using numerical method to solve ADE Numerical dispersion appears in the numerical results This study applies meshless mehod ot solve ADE Multiquardric radio basis function collocation method (MQ-RBFCM) is used to model the advection-dispersion solute transport The result shows good match with the analytical solution Sensitivity analysis of parameters in MQ-RBFCM focus on shape parameter time marching interval time weighting parameter and time integration schemes Marching nodal arrangements are proposed to reduce numerical dispersion The allocation of nodes for meshless method is very flexible The marching nodal arrangement allocates the dense nodes around the front and moving with time The total number of nodes can be effectively reduced and keep the same accuracy compared with uniform arrangement For efficiency the result shows that the marching nodal arrangement cannot significantly reduce the simulation time in small domain because it needs to relocate the nodes and interpolate the initial value every time step For large domain the marching nodal arrangement shows the superiority classical since reduction in the nodal distance will rapidly increase the nodes number in uniform arrangement to cause the difficult of solving linear algebraic system

Date of Award	2015 Aug 25
Original language	English
Supervisor	Kuo-Chin Hsu (Supervisor)