Model and simulation:two-dimensional model fa(P)-jlGi/P.+BJ+GiP.Py+G(P,+B.F+G(Py-B.F] PPi/or ,cG.+g,+Ca+号cG 2 un=ou;/or u=ou;/ori+ou;/or f4,PF月=-uhx-4y几n-4n a=QP2+02P, mwy=QnPy+Q12P:nky=Q4P:Py fg=-E-PModel and simulation: two-dimensional model [ G (P P ) G P P G (P P ) G (P P ) ] 2 1 f (P ) 2 44 x,y y,x 2 12 x,x y,y 44 x,y y,x 2 y,y 2 g i,j  11 x,x        Pi, j= ∂Pi /∂ rj C u , 2 1 C ( u u ) C u u 2 1 f ( u ) 2 12 x,x y,y 44 x,y 2 y,y 2 u i,j  11 x,x    uii = ∂ ui /∂ ri, ui, j= ∂ uj /∂ ri + ∂ ui /∂ rj c i,j x,x xx y,y yy x,y xy f (u ,P(r))  u   u   u    xx=Q11 Px 2+Q12Py 2 ; yy=Q11 Py 2+Q12Px 2 ; xy=Q44PxPy fE= −E·P