Matlab Solving Differential Equation using Runge Kutta

1 次查看（过去 30 天）
Jasjot Kaur
Jasjot Kaur 2019-10-25
回答： James Tursa 2019-10-25
clc;
h = 50;
x = 0: h: 0.025;
w = 3553.6312;
M = 110.361;
f = 0.02;
A = 24;
Cd = 0.32;
P = 1925.637;
F = 16.80444124;
x(1) = 700; % initial condition
F_yx = @(y, x)(P - f.*w - 0.00118.*Cd * A * y ^ 2) / (M); % function
for i = 1: (length(x) - 1) % calculation loop
k_1 = F_xy(x(i), xy(i));
k_2 = F_xy(x(i) + 0.5 * h, y(i) + 0.5 * h * k_1);
k_3 = F_xy((x(i) + 0.5 * h), (y(i) + 0.5 * h * k_2));
k_4 = F_xy((x(i) + h), (y(i) + k_3 * h));
y(i + 1) = y(i) + (1 / 6) * (k_1 + 2 * k_2 + 2 * k_3 + k_4) * h; % main equation
end
syms y(x)
ode = diff(y, x) - F * y == 0;
ySol(x) = dsolve(ode);
fimplicit(y(x))

请先登录，再回答此问题。

回答（1 个）

James Tursa
James Tursa 2019-10-25
In this line:
k_1 = F_xy(x(i), xy(i));
You've got xy(i) as an argument, but there is no xy variable. I think you meant y(i) here.
In this line:
F_yx = @(y, x)(P - f.*w - 0.00118.*Cd * A * y ^ 2) / (M); % function
You've got the order of the inputs as (y,x), but in your downstream code you have the order of the inputs as (x,y). Change your function to use the (x,y) order.
This initial condition:
x(1) = 700; % initial condition
I suspect should apply to y(1), not x(1). You already have the x vector defined above.

类别

在 Help Center 和 File Exchange 中查找有关 Ordinary Differential Equations 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by