Example 10.5-2: Part a

Steady Flow of a non-isothermal film: 
The only component of velocity is the z component. It only changes in the x direction as shown in Fig. 2.2-2
Temperature also only varies in the x direction.
>  restart;
>  s:=dsolve({diff(T(x),x,x),T(0)=T0,T(delta)=Td},T(x)):
>  assign(s);
>  T:=unapply(T(x),x);
>  mu:=proc(x) eq. 10.5-19a
>   local T1;global T, B;
>   T1:=T(x);
>   mu0*exp(B*((1/T1)-(1/T0)));
>  end:
>  mu(0);
>  mud:=mu(delta);
>  A:=mud/mu0;
>  muapp:=proc(x) eq. 10.5-19c
>   global delta, mu, mu0, A;
>   mu0*A^(x/delta);
>   end:
>  muapp(0);
>  muapp(delta);
>  muapp(delta/2);
Data for water from plot and fit of data in Table 1.1-1
>  B:=1868.6; mu0:=1.787; T0:=273.15; Td:=373.15;
>  muapp(.6*delta);

>  mu(.6*delta); From Table 1.1-1 it should be .4665 at 60C

>  mus:=[1.787,1.0019,0.6530,0.4665,0.3548,0.2821]; From Table 1.1-1 mu in cp.
>  Ts:=[0,20,40,60,80,100]; The temperatures in the table in C.
>  Tmus:=[[Ts[n]/100,mus[n]]$n=1...6]; Making a list of lists.
>  with(plots):
>  p1:=plot(Tmus,style=point,symbol=circle):
>  p2:=plot([mu(x*delta),muapp(x*delta)],x=0...1,color=[red,green]):
>  display([p1,p2]); The red curve is the value from mu, the green one from the approximate one and the circles are the data in the Table.

>