ep3_p3.m

此代码展示了Euler计算方法与差分方法

%  Ep3_p3: << 实验三 >>  改进的Euler法 (预报-校正法)
%  Designed by FGH

h= 0.05;
H= 120; Vw= 450; Ve= 90;

clear x y;
tk= 0; 
k= 1;
% (3.28)
x(1)= 0; y(1)= 0;
while y(k) < H
   tk1= tk+h;
   % (3.26)
   xk1= x(k) + Vw*h*(Ve*tk-x(k))/sqrt((Ve*tk-x(k))^2+(H-y(k))^2);
   % (3.27)
   yk1= y(k) + Vw*h/sqrt(1+((Ve*tk-x(k))/(H-y(k)))^2);
   % (3.24)
   x(k+1)= 0.5*(xk1 + x(k) + Vw*h/sqrt(1+((H-yk1)/(Ve*tk1-xk1))^2));
   % (3.25)
   y(k+1)= 0.5*(yk1 + y(k) + Vw*h/sqrt(1+((Ve*tk1-xk1)/(H-yk1))^2));
   
   tk= tk+h; k= k+1;
end
x
y
sprintf(' k = %d , tk = %7.4f \n',k-1,tk)
sprintf(' L = %8.4f , T = %8.4f \n',x(k),x(k)/Ve)