| Author | Message | |||
     scorpion Member Username: scorpion Post Number: 18 Registered: 03-2007 |
Hello everyone. I have such a problem. I have 3 independent variables vx,vy,p, equations for which are the following: p: del2(p)=0 vx: dt(vx)=visc*del2(vx) + a0*sin(2*pi*omega*t) vy: dt(vy)=visc*del2(vy) Boundary conditions do not contain any expressions that contain them. But when I change BC's for vx,vy picture of p gets different. That's weird. Please see my script.
I have commeted BC's {value(vx)=0 value(vy)=0}. But when I make them active my P distribution changes. I do not understand why. Could you please help me. | |||
| rgnelson Moderator Username: rgnelson Post Number: 1333 Registered: 06-2003 |
The VELOCITY boundary condition was introduced for use with moving meshes. I don't know what you intend when you apply a velocity to a pressure variable, nor do I know what FlexPDE will do with it. | |||
| scorpion Member Username: scorpion Post Number: 19 Registered: 03-2007 |
Robert, I'm trying to make the following problem. Something like a piston with a spring on one end. It is full of water. F=-kx, x=time_integral(vx). So I have pressure p=0 on one end and pressure p=time_integral(vx) on another. On two other boundaries I have natural(p)=0. But FlexPDE does not allow me to use time_integrals in BC's. That's why I tried to use dp/dt=vx. So velocity(p) was meant to be a time derivative of a pressure. | |||
| scorpion Member Username: scorpion Post Number: 20 Registered: 03-2007 |
I've solved the problem, don't worry. Thanks for help. |
