The model of fixed-bed adsorption column

Fluid phase:

PDE:= diff(U(x, tau),tau)+ psi*Theta*diff(U(x, tau),x)-(1/Pe)*psi*Theta*diff(U(x, tau),$(x, 2))=-3*psi*xi*(U(x, tau)-Q/K);

IBC:={U(x, 0) = 0,U(0, tau) = 1+(1/Pe)*(D[1](U))(0, tau),(D[1](U))(1, tau)=0};

Particle:

PDE:= diff(Q(r, tau), tau) = diff(Q(r, tau), $(r, 2))+(2/r)*diff(Q(r, tau),r);

IBC:={Q(r, 0) = 0,(D[1](Q))(0, tau) = 0,(1/K)*(D[1](Q))(1, tau)=xi*(U-Q(1, tau)/K)};

Pe:=0.01:

psi:=6780:

Theta:=3.0:

xi:=10000:

I will really appreciate your help. Thanks in anticipation.

Hi guys,

I'm trying to draw a phase portrait based on a system of differential equations, but executing the DEplot command gives me the response in the title. 

The command I entered is this one :

DEplot(sysdif,[u(t),nu(t)],t=0..50,{[u(0)=0.831,nu(0)=0.7]},linecolor=red,numpoints=1000, thickness=1, u=0.5...1, nu=0.6...1, color=black);

the system of equation is this one :

eqd1 := diff(u(t), t) = u(t)*[-gamma + (rho)/(mu - nu(t)) - delta*u(t) + pii - (tau)/(alpha + epsilon*exp(-beta*((omega-u(t))/(kappa-u(t)))))] ;
eqd2 := diff(nu(t), t) = nu(t)*[(omega-u(t))/(kappa-u(t)) - (tau)/(alpha+epsilon*exp(-beta*((omega-u(t))/(kappa-u(t)))))] ;

the model is calibrated. I understand that maple cannot store a kind of number but even changing the parameters won't help. I've been looking for people with same error message but using solutions provided by forum members don't work. Before getting that error message i did have the one with "vars must be declared as a list ..." so I did :

u:='u' ;

nu:='nu';

but now I have the error  "unable to store  '[HFloat(0.005711776872341132)]' when datatype=float[8]".

Does anybody have an idea of the solution to my problem ?

Thanks for your time,

best regards,

Louis

I'm just using it this way:

with(QDifferenceEquations):
QPochhammer(-1,5,10)

Error, (in QDifferenceEquations:-QPochhammer) wrong type of arguments

Am I doing something terribly wrong???

Hi,

     I'm trying to numerically solve a PDE in Maple for different boundary conditions, however I'm having trouble even getting Maple to numerically solve it for simple boundary conditions.

I have cylindrical coordinates, r, z, theta, and I treat r = r(z, theta) for convenience to plot my solution surface. The initial coundary condition is that at z = epsilon (z = 0 is singular) , r = constant and of course r is periodic in theta. This is just a circle, and the analytical solution is know to be a half-sphere  r = sqrt(R^2 - z^2). I entered my initial boundary conditions into Maple, but it doesn't like the periodic one

IBC := { r(epsilon, theta) = R - epsilon__r,
              r(z, 0) = r(z, 2*Pi) };

pdsolve(
  PDE,
  IBC,
  numeric,
  indepvars = [z, theta],
  time = z,
  range = 0..2*Pi);
Error, (in pdsolve/numeric/par_hyp) Incorrect number of boundary conditions, expected 2, got 1

I'm not sure how to make this work, and then generalize it to more arbitrary intial slices r(epsilon, theta) = f(theta).

Here's the attached worksheet, ForMaplePrimesSUbmission.mw

Any help is appreciated,

Thanks

I have written some statements in maple and when integrating a vector I encounter an error . whats the problem? the error is:

Error, (in evalf/Ei/taylor) unsupported type of index, 1.

F1 := ScalarMultiply(Phi^%T, f);
F := int(F1, x = 0 .. 1);

which f is exp(x-t) and Phi is a vectror.

r := sqrt(x^2+y^2+z^2);
divE := diff(e*x/(4*Pi*r^3), x)+diff(e*x/(4*Pi*r^3), y)+diff(e*x/(4*Pi*r^3),z);
simplify(divE);

of a square matrix having its entries 1,2,...16? See http://oeis.org/A085000 for info.

I want to plot this contour 4x^2+9y^2=160  onto the same f(x,y)=4x^2+9y^2.  The error I keep getting is

Error, (in plot3d) first argument must be either in standard or parametric form

Thanks

I can;t seem to get DSOLVE working.  Will some kindly soul please send me a complete example, starting with an f(x) & clearly documented?   Many thanks.

AB

Suppose I have a file, test.txt, which the content is

2
2 0.0 0.0 0.0
1 0.0 0.0 1.6

I would like to save 

Z:=2;

C[1,1]:=2;C[2,1]:=0.0;C[3,1]:=0.0;C[4,1]:=0.0;

C[1,2]:=1;C[2,2]:=0.0;C[3,2]:=0.0;C[4,2]:=1.6;

However, if I use readdata("...",4), seems it do not work.

Is there any flexible command in maple can readfile with different column? Thank you very much!

I am having difficulty with the contourplot3d.  When I hit enter it comes back with a blank plot.  Either Im doing somthing wrong or my machine can't handle it.

restart;

with(plots);

Eq1 := diff(f(eta), eta, eta, eta)+f(eta)*(diff(f(eta), eta, eta))-(diff(f(eta), eta))^2-M^2*(diff(f(eta), eta))+B(f(eta)*(diff(f(eta), eta, eta))*(diff(f(eta), eta))-f(eta)^2*(diff(f(eta), eta, eta, eta))) = 0;

Eq2 := (diff(theta(eta), eta, eta))/Pr+f(eta)*(diff(theta(eta), eta))-2*(diff(f(eta), eta))*theta(eta) = 0;

Pr := 1

M := 1

S := 0

epsilon := 1

blt := 10

bcs1 := f(0) = S, (D(f))(0) = epsilon, (D(f))(blt) = 0;

bcs2 := theta(0) = 1, theta(blt) = 0;

L := [0, .2, .4, .6, .8, 1.2];

for k to 6 do R := dsolve(eval({Eq1, Eq2, bcs1, bcs2}, B = L[k]), [f(eta), theta(eta)], numeric, output = listprocedure); X1 || k := rhs(R[3]); X2 || k := rhs(R[4]); Y1 || k := rhs(R[5]); Y2 || k := -rhs(R[6]) end do:

print([(X2 || (1 .. 6))(0)])

Consider the equation

eqn1:=5^(2*abs(y-1)+2) = (1/15625)*625^abs(y-1);

and note that

eval( eqn1, y=-3);
eval( eqn1, y=5);

both return valid solutions. So why does

testeq(eqn1);

throw a numeric exception.

Given the manual description of testeq(), I would expect it to return either true or FAIL - but not a numeric exceprion!!!!

Any ideas?

Hi, is it possible to instantly start the display of plot animations after they are generated in maple? I searched for answers in the documentation and on the internet but couldn't find a solution. I would like to skip the step of manually clicking the plot and the "play animation" button.