# How to solve coupled transport equations

 Register Blogs Members List Search Today's Posts Mark Forums Read

 November 20, 2008, 19:21 Hi All I would like to solv #1 Senior Member   Vishal Nandigana Join Date: Mar 2009 Location: Champaign, Illinois, U.S.A Posts: 208 Rep Power: 16 Hi All I would like to solve coupled transport equations (not using relaxation technique). Can someone help me which tutorial I should go about looking to solve my problem. These are my equations ddt(C1) = - K1 * laplcian(C1) - K2 * laplacian (phi) ddt(C2) = - K1 * laplcian(C2) - K2 * laplacian (phi) K3 * laplacian (phi) = K4 where k1,k2,k3,k4 are some constant values.. Kindly help me out. I tried searching in the forum and could not get any information pertaining to this. I don't think I can use conjugate heat transfer solver for this. Vishal

 November 21, 2008, 01:22 Look at scalarTransportFoam in #2 Member   Prashant Ojha Join Date: Mar 2009 Posts: 38 Rep Power: 15 Look at scalarTransportFoam in the '\$FOAM_SOLVERS/basic' folder

 November 21, 2008, 02:41 What about solving your equati #3 Member   Christian Winkler Join Date: Mar 2009 Location: Mannheim, Germany Posts: 63 Rep Power: 15 What about solving your equations in a segregated manner? First solve: K3 * laplacian (phi) = K4 and then: ddt(C1) = - K1 * laplcian(C1) - K2 * laplacian (phi) ddt(C2) = - K1 * laplcian(C2) - K2 * laplacian (phi) or is there any coupling in C1 and C2? Best regards Christian

 November 21, 2008, 16:53 Hi Christian and Prashanth, #4 Senior Member   Vishal Nandigana Join Date: Mar 2009 Location: Champaign, Illinois, U.S.A Posts: 208 Rep Power: 16 Hi Christian and Prashanth, Thanks a lot for the reply. I just missed one term in my equation. The equations look like this, ddt(C1) = K1 * laplcian(C1) + K2 * laplacian (phi) ddt(C2) = K1 * laplcian(C2) + K2 * laplacian (phi) K3 * laplacian (phi) = K4 * f(C1) + K5 * f(C2) (Further this is a stiff equation) where k1,k2,k3,k4 and k5 are some constant values.. I want to solve them directly and not using relaxation procedure. Kindly offer some suggestions as to how to go about solving them. May I know which tutorial i have to follow. Thanking You Vishal

 November 22, 2008, 17:43 Thanks a lot for the reply. I #5 Senior Member   Vishal Nandigana Join Date: Mar 2009 Location: Champaign, Illinois, U.S.A Posts: 208 Rep Power: 16 Thanks a lot for the reply. I just missed one term in my equation. The equations look like this, ddt(C1) = K1 * laplcian(C1) + K2 * laplacian (phi) ddt(C2) = K1 * laplcian(C2) + K2 * laplacian (phi) K3 * laplacian (phi) = K4 * f(C1) + K5 * f(C2) (Further this is a stiff equation) where k1,k2,k3,k4 and k5 are some constant values.. f(C1) and f(C2) means the equation is a function of C1 and C2. I want to solve them directly and not using relaxation procedure. Kindly offer some suggestions as to how to go about solving them. May I know which tutorial i have to follow. Thanking You Vishal