RR ̈(1-R ̇/C)+3/2 R ̇^2 (1-R ̇/3C)=(1+R ̇/C)(H-(3q+├ τ_rr ┤|R)/ρ)+R/C[H ̇(1-R ̇/C)-(3q ̇+├ τ_rr ┤|R)/ρ] (1) H=1/ρ n/(n-1) (p_0+p+B){[(p_1-(2σ/R)+├ τ_rr ┤|R+B)/(p_0+p+B)]-1} (2) C=c_0 〖[(p_1-(2σ/R)+├ τ_rr ┤|R+B)/(p_0+p+B)]〗^(n-1/2n) (3) p_1=(p_0+2σ/R)〖(R_0/R)〗^3γ (4) q+φq ̇+φ R ̇/R ├ τ_rr ┤|R=1/3[-4G/3 (1-〖R_0〗^3/R^3 -4μ R ̇/R)] (5) ├ τ_rr ┤|R+φ├ τ ̇_rr ┤|R=-4G/3 (1-〖R_0〗^3/R^3 -4μ R ̇/R) (6)怎么通过MATLAB解这六个微分方程组
时间: 2023-07-27 09:06:30 浏览: 70
要通过MATLAB求解这六个微分方程组,可以使用MATLAB自带的ODE求解器函数,例如ode45。具体步骤如下:
1.将微分方程组转化为MATLAB函数形式,例如将(1)式写成以下形式:
function dydt = equations(t, y, p0, p, B, sigma, G, mu, rho, n, c0, gamma, R0)
R = y(1);
v = y(2);
p1 = (p0+2*sigma/R)*(R0/R)^3*gamma;
tau_rr = -4*G/3*(1-R0^3/R^3-4*mu*v/R)+3*q+phi*v*tau_rr/R;
H = 1/rho*n/(n-1)*(p0+p+B)*((p1-(2*sigma/R)+abs(tau_rr)+B)/(p0+p+B)-1);
C = c0*((p1-(2*sigma/R)+abs(tau_rr)+B)/(p0+p+B))^(n-1/2/n);
dydt = [v; 1/R*(1/R*R*dydt(1)*(1-v/C)+3/2*v^2*(1-v/(3*C))-(1+v/C)*(H-tau_rr/rho+R/C*(H*(1-v/C)-tau_rr/rho*(3*q+phi*v*tau_rr/R)))];
end
2.定义初始条件,例如R0=1.0,v0=0.0
3.选择ODE求解器函数,例如ode45,并设置时间范围和初始值
4.调用ODE求解器函数并绘制图形
示例代码:
function solve_equations()
% 定义常数
p0 = 1.0;
p = 1.0;
B = 1.0;
sigma = 1.0;
G = 1.0;
mu = 1.0;
rho = 1.0;
n = 2.0;
c0 = 1.0;
gamma = 1.0;
R0 = 1.0;
% 定义初始条件
y0 = [R0; 0.0];
% 设置时间范围
tspan = [0.0, 10.0];
% 调用ode45求解微分方程组
[t, y] = ode45(@(t, y) equations(t, y, p0, p, B, sigma, G, mu, rho, n, c0, gamma, R0), tspan, y0);
% 绘制图形
plot(t, y(:, 1), 'r', t, y(:, 2), 'b');
legend('R', 'v');
xlabel('t');
ylabel('R, v');
end
% 调用函数并绘制图形
solve_equations();
阅读全文