| Author | Message | ||||||||
     Nadeem Ansari (nadeem) New member Username: nadeem Post Number: 1 Registered: 11-2006 |
I am using flexpde 5.0.10 3D version. I am solving a 1D problem where I have to provide the initial value from a table. I have a table with variable U10 and axes Lx1 Flexpde is not reading the table. I have uploaded the data file and the pde file. .
I would appreciate any help. | ||||||||
| Nadeem Ansari (nadeem) New member Username: nadeem Post Number: 2 Registered: 11-2006 |
I think that there are some uploading errors. My data file cn8.txt is like this Lx1 -10 -9.9 -9.8 ...... data{u10} 2.567564 2.4544 ... where -10<Lx1<10 is the axes range and then the corresponding u10 values. and i am using it in the pde script as DEFINITIONS { parameter definitions } u10=Table('cn8.txt') m=0.8 u11=m/3*u10 t1=80 INITIAL VALUES u1=u11 u2=0 v1=u11 v2=0 then I have to define the bounderies as BOUNDARIES { The domain definition } region 1 start(-Lx1) natural(u1)=0 natural(u2)=0 natural(v1)=0 natural(v2)=0 line to (Lx1) natural(u1)=0 natural(u2)=0 natural(v1)=0 natural(v2)=0 | ||||||||
| Nadeem Ansari (nadeem) Junior Member Username: nadeem Post Number: 3 Registered: 11-2006 |
I think that there are some uploading errors. My data file cn8.txt is like this Lx1 -10 -9.9 -9.8 ...... data{u10} 2.567564 2.4544 ... where -10<Lx1<10 is the axes range and then the corresponding u10 values. and i am using it in the pde script as DEFINITIONS { parameter definitions } u10=Table('cn8.txt') m=0.8 u11=m/3*u10 t1=80 INITIAL VALUES u1=u11 u2=0 v1=u11 v2=0 then I have to define the bounderies as BOUNDARIES { The domain definition } region 1 start(-Lx1) natural(u1)=0 natural(u2)=0 natural(v1)=0 natural(v2)=0 line to (Lx1) natural(u1)=0 natural(u2)=0 natural(v1)=0 natural(v2)=0 | ||||||||
| Robert G. Nelson (rgnelson) Moderator Username: rgnelson Post Number: 700 Registered: 06-2003 |
You have declared LX1 as the coordinate of the table. But in your script, LX1 is apparently a fixed number. So you will never get any result from the table except the one at the value of LX1. I suspect what you want is to use "X" as the table coordinate definition. | ||||||||
| Nadeem Ansari (nadeem) Member Username: nadeem Post Number: 4 Registered: 11-2006 |
Actually I have to use the data for u1 as the initial condition along the set values of x-coordinate (I am calling it Lx1, but I have changed it to x). Then I have to look at the time-dependent behaiour of different parameters u1, u2, v1, v2. In 1D case I am defining my line starting from -10 to 10, i.e. -10<x<10. When I run the script it opens the data file and gives me the message that (-)10 is an illegal symbol. below is my full script. SELECT smoothinit off contourgrid=80 errlim 0.00001 thermal_colors on COORDINATES cartesian1 VARIABLES { system variables } u1(threshold=1) u2(threshold=1) v1(threshold=1) v2(threshold=1) DEFINITIONS { parameter definitions } u10=Table('cn8.txt') m=0.8 u11=m/3*u10 t1=80 INITIAL VALUES u1=u11 u2=0 v1=u11 v2=0 EQUATIONS u1: -1/2*dxx(u2)-((u1^2+u2^2)+2*(v1^2+v2^2))*u2=dt(u1) u2: 1/2*dxx(u1)-((u1^2+u2^2)+2*(v1^2+v2^2))*u1=dt(u2) v1: -1/2*dxx(v2)-(2*(u1^2+u2^2)+(v1^2+v2^2))*v2=dt(v1) v2: 1/2*dxx(v1)+(2*(u1^2+u2^2)+(v1^2+v2^2))*v1=dt(v2) CONSTRAINTS { Integral constraints } BOUNDARIES { The domain definition } region 1 start(-10) natural(u1)=0 natural(u2)=0 natural(v1)=0 natural(v2)=0 line to (10) natural(u1)=0 natural(u2)=0 natural(v1)=0 natural(v2)=0 { if time dependent } time 0.0 to t1 MONITORS { show progress } PLOTS { save result displays } for t=0.0 by (t1/20) to t1 MONITORS { show progress } PLOTS { save result displays } elevation((u1^2+u2^2)^(1/2)) from (-10) to (10) {export format "#x#b#1" file="darkhigh.txt"} elevation((v1^2+v2^2)^(1/2)) from (-10) to (10) HISTORY((v1^2+v2^2)^(1/2)) AT (3) END | ||||||||
| Robert G. Nelson (rgnelson) Moderator Username: rgnelson Post Number: 701 Registered: 06-2003 |
Send your script and data file to support@pdesolutions.com | ||||||||
| xiaopuzhang (schorpple_zhang) New member Username: schorpple_zhang Post Number: 1 Registered: 11-2006 |
I want the descriptor of the magnetic potential around a coil in cylindrical geometry introduced in the FlexPDE help. I don't know where to download the file. who knows? Thanks very much. | ||||||||
| xiaopuzhang (schorpple_zhang) New member Username: schorpple_zhang Post Number: 2 Registered: 11-2006 |
when I run the programme, the Error window display "initial mesh size (3036)"exceed node limit. what is wrong with my programme? who could answer my question? thanks very much | ||||||||
| xiaopuzhang (schorpple_zhang) Junior Member Username: schorpple_zhang Post Number: 3 Registered: 11-2006 |
when I run the programme, the Error window display "initial mesh size (3036)"exceed node limit. what is wrong with my programme? who could answer my question? thanks very much | ||||||||
| Robert G. Nelson (rgnelson) Moderator Username: rgnelson Post Number: 704 Registered: 06-2003 |
I presume you are using the free Student version of FlexPDE. This version places limits on the size of the mesh you can use. If you specify a domain with small features or a small mesh size control, the initial mesh that FlexPDE constructs may be much larger than the Student version limit. In this case, FlexPDE will reject the problem as being outside the capabilities of the free Student version. You will have to define a simpler domain or a smaller NGRID, or a larger MESH_SPACING, in order to reduce the number of mesh nodes to less than the limit. |
