can it be possible to use odeVectorField
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이전 댓글 표시
syms f(x) g(x) h(x) Pr Nb Nt Le
[V] = odeToVectorField( diff(f,3) - diff(f)^2 + f * diff(f,2) == 0,diff(g,2) + Pr * ( f * diff(g) + Nb * diff(g)* diff(h)+ Nt * diff(g)^2) == 0,...
diff(h,2) + Le * f * diff(h) + ( Nt/Nb ) * Pr * ( f * diff(g) + Nb * diff(g)* diff(h)+ Nt * diff(g)^2)== 0)
%% I want to incorporate the expression of [V] into below code, but I am getting wrong expression (not as dydx below)
%%% can it be used in bvp 4c code and in which style
function main
Pr=10; Le=10; Nt=.1;Nb=.1;
xa=0;xb=6;solinit=bvpinit(linspace(xa,xb,1000),[0 1 1 1 0 0 0]);options=[];
sol=bvp4c(@ode,@bc,solinit,options);xint=linspace(xa,xb,100);S=deval(sol,xint);
function res=bc(ya,yb)
res=[ya(1); ya(2)-1; ya(4)-1; ya(6)-1; yb(2); yb(4); yb(6)];
end
function dydx=ode(x,y)
dydx=[y(2); y(3); y(2)^2 - y(3)*y(1); y(5); - Pr*(y(1)*y(5) + Nb*y(5)*y(7) + Nt*y(5)^2);
y(7); - Le*y(7)*y(1) + (Nt/Nb)*Pr*(y(1)*y(5) + Nb*y(5)*y(7) + Nt*y(5)^2)];
end
end
댓글 수: 3
MINATI PATRA
2020년 5월 23일
Dear Darova that M gives wrong code as you can compare and another question is how to include in bvp 4c code
답변 (1개)
darova
2020년 5월 24일
Try this
clc,clear
syms f(x) g(x) h(x) x Y
Pr=10;
Le=10;
Nt=.1;
Nb=.1;
[V,y1] = odeToVectorField( diff(f,3) - diff(f)^2 + f * diff(f,2) == 0,...
diff(g,2) + Pr * ( f * diff(g) + Nb * diff(g)* diff(h)+ Nt * diff(g)^2) == 0,...
diff(h,2) + Le * f * diff(h) + ( Nt/Nb ) * Pr * ( f * diff(g) + Nb * diff(g)* diff(h)+ Nt * diff(g)^2)== 0)
F = matlabFunction(V,'vars', [x Y]);
bc = @(ya,yb) [ya(1) % g
ya(2)-1 % Dg
ya(4)-1 % f
ya(6)-1 % Df
yb(2) % D2f
yb(4) % h
yb(6)]; % dh
xa=0;
xb=6;
solinit = bvpinit(linspace(xa,xb,1000),[0 1 1 1 0 0 0]);
options = [];
sol = bvp4c(F,bc,solinit,options);
plot(sol.x,sol.y)
Change boundary conditions if needed
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