| Author | Message | |||
     Gianfranco Prota (gianf) New member Username: gianf Post Number: 1 Registered: 12-2008 |
Dear Mr Nelson, I need help. I have a box 2D (a rectangle) with the wall bottom hot and the wall upper cold. Inside there is air that moves through the difference of temperature and inclination of the box. I would like the box is shift upwards of 1 degree compared to the previous position whenever flexpde finds the solution of the equations: vx: dens*[(vx)*dx(vx)+(vy)*dy(vx)]+dx(p) - Fx - visc* del2(vx)= 0 vy: dens*[(vx)*dx(vy)+(vy)*dy(vy)]+dy(p) - Fy - visc* del2(vy)= 0 p: del2(p)- dy(Fy)-dx(Fx)- 1e4* div(v)= 0 Tp: -cond*del2(Tp)+ rcp*[vx*dx(Tp)+ vy*dy(Tp)]=0 With: Fx= dens*beta*g*cos(b)*(Tp-Tm) Fy= dens*beta*g*sin(b)*(Tp-Tm) b that must depend on the time and varies between 0 and Ð/4. b must follow a dependence on time and increase each time flexpde find the solution of vx, vy, p and Tp equations. Flexpde must give me in MONITORS the solutions at every inclination consider. I post the script at fixed angle where I don’t know restore the dependence of b by time. Regards, Gianfranco Prota
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| Marek Nelson (mgnelson) Moderator Username: mgnelson Post Number: 98 Registered: 07-2007 |
The easiest way to do this would be to use a STAGED definition of b. See "STAGED Definitions" in the Help index. (This is not the same as being dependent on time - but progresses the value in stages.) Adding the following to your script, should do what you are asking for: SELECT stages=90 DEFINITIONS increment=2*PI/360 {one degree in radians} b=stage*increment {stage b from 1 to 90 degrees (but in radians)} When FlexPDE has finished solving the first stage with b=1*increment, then it will continue solving the system with b=2*increment and so on. PS - It looks to me that your boundary conditions may not be correct, but I have not looked into this. |
