time looping or increment not updating
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Hi all,
I have to time loop/time increment with the code: t=deltat:deltat:3600*5;
Even by varying the time t in the for loop I could not find any change. Please suggest me whether the time looping which I had mentioned is correct or else I have to follow some other steps.
When I plot with the output value of F vs -Z at any time I get the same ans. Simila case with plot u vs -Z.
Please help me in time looping/incrementing. Thank you in advance
alpha=(17*pi)/180; %slope angle
dz=200; %depth of water table from the suface
dlz=400; % toltal depth of slope
fi=(25*pi)/180; %friction angle
C=0.004; %4 kpa=0.4 N/cm^2
gsat=0.021; %21 kN/m^3
gw=0.0098; %9.81 Kn/m^3
Dzero=4; %0.0004m^2/s
ksat=1e-3; %e-5 m/s
iz=2e-4; %iz=7.2 mm/h= 2e-4 cm/s
deltat=10; %time step
deltaz=0.8; %space step
T=12*60*60; %time duration of rainfall= 12h to seconds
e=(deltat/deltaz^2)*Dzero*cos(17*pi/180)*cos(17*pi/180);
n=500; % number of nodes
nt=4320; %time step, based on T
Z=linspace(deltaz,400,500); %Depth in cm
%Setup sparse matrix
si=(Z-dz)*cos(alpha)*cos(alpha); %Initial condition ...i.e.
%pressure head @t=0 all along the depth
if true
% code
end
si=si';
a=-e*ones(n,1); % lower Triagonal vectors
% a(1)=0; a(n)=-114.314; a=a';
b=116.314*ones(n,1); % Diagonal vectors
b=b';
c=-e*ones(n-1,1);% Upper trigonal vector
% c(1)=-114.314; c(n)=0; c=c';
d=ones*(n-2:1);
for t=deltat:deltat:3600*5;
for w=2:499
d(w)=e*si(w-1)-112.314*si(w)+e*si(w+1); % Rhs vector
end
if t>T
d(1)=-112.314*si(1)+114.314*si(2)-130.686;
else
d(1)=-112.314*si(1)+114.314*si(2)-167.264; % t<=T
end
d(500)=114.314*si(499)-112.314*si(500)+167.264; % Boundary condition...
%at the bottom of the slope at all values of t
end
A=ones*(n-1:1);
S=ones*(n-1:1);
d=d';
A(1)=b(1); % A(1)=alpha one=b(1)
S(1)=d(1); % S(1)=Rhs(1)
for i=2:n %varies from 2 to n
A(i)=b(i)-((a(i)/(A(i-1))*c(i-1)));
S(i)=d(i)+((a(i)/(A(i-1))*S(i-1)));
end
A=A';
S=S';
u(n)=S(n)/A(n); %u(N-1)=S(N-1)/A(N-1), "M*u=S", solve for u with M known...
% ... trigonal matrix and S= known Rhs vector
for t=deltat:deltat:3600*18;
for j=n-1:-1:1
% for w=10:10:4320
u(j)=(1/A(j))*(S(j)+(c(j)*u(j+1)));
end
end
% disp([t u]);
u=u';
if u(1)<=0 %Check for ponding
Fs=(tan(fi)/tan(alpha))*ones(n,1); %Gravity component
Fs=Fs';
Fw=(-u*gw*tan(fi))./(gsat*Z'*sin(alpha)*cos(alpha)); %Water pressure ...
%component
Fw=Fw';
Fc=C./(gsat*Z'.*sin(alpha)*cos(alpha)); %Cohesion component
Fc=Fc';
F=Fs+Fw+Fc; %FOS for slope
elseif soln(1)<=0 && (t<T)
d(1)=-114.314*si(1)+114.314*si(2)-130.686;
elseif soln(1)>0 &&(t<T)
soln(1)=0;
else
d(1)=-114.314*si(1)+114.314*si(2)-167.264;
end
Fs=(tan(fi)/tan(alpha))*ones(n,1); %Gravity component
Fs=Fs';
Fw=(-u*gw*tan(fi))./(gsat*Z'*sin(alpha)*cos(alpha)); %Water pressure ...
%component
Fw=Fw';
Fc=C./(gsat*Z'.*sin(alpha)*cos(alpha)); %Cohesion component
Fc=Fc';
F=Fs+Fw+Fc; %FOS for slope
if true
% code
end
2 个评论
Geoff Hayes
2014-9-26
When you say Even by varying the time t in the for loop I could not find any change, which t are you varying? t is an index in the for loop, so that can't be it. Is it the deltat that you are changing, and if so, to what?
Stephen23
2014-9-26
As an aside, you should avoid naming variables i and j, as these are the inbuilt imaginary unit . Accidentally overloading inbuilt functions and variables can cause all sorts of very-difficult-to-figure-out problems later...
回答（2 个）
Star Strider
2014-9-26
0 个投票
I didn’t run your code, but it seems that none of your variables inside either of your ‘t’ loops are actually functions of ‘t’. They simply loop endlessly over the same values.
2 个评论
Star Strider
2014-9-27
advaita vedanta’s ‘Answer’ moved here:
@Star strider, yes what you mentioned I agree, I am confused on how to assign.
Thank you
Star Strider
2014-9-27
What are your original functions?
How are they functions of time?
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