MATLAB: Pressure as a function of crank angle

for looppressure

I need to plot pressure as a function of crank angle using the following eqaution p=(pm*SQRT(1-c^2))/(1-c*cos(alpha-delta)). Ive calculated all the required variables below but Im having trouble plotting with a for loop, any suggestions please?
V_se=7000;
V_sc=250;
v=V_sc/V_se;
T_e=333;
T_c=293;
t=T_c/T_e;
phi=pi/2;
T_r=312.6;
%let V_de=1000, V_r=500, V_dc=50
V_de=1000;
V_r=500;
V_dc=50;
V_d=V_de+V_r+V_dc;
T_d=324.7;
s=(V_d/V_se)*(T_c/T_d);
B=t+1+v+2*s;
A=sqrt(t^2-2*t+1+2*(t-1)*v*cos(phi)+v^2);
c=A/B;
p_m=1.01325;
%p_max=p_m*(sqrt(1+c)/sqrt(1-c));
%p_min=p_m*(sqrt(1-c)/sqrt(1+c));
delta=atan((v*sin(phi))/(t-1+v*cos(phi)));
for alpha=0:2*pi
p=(p_m*sqrt(1-c^2))/(1-c*cos(alpha-delta));
plot (alpha,p)
end,.,.

Best Answer

Two options for the plot, depending on what you want to do:
Plot in the loop: 
figure
hold all
for alpha=0:0.2:2*pi
  p=(p_m*sqrt(1-c^2))/(1-c*cos(alpha-delta));
  plot (alpha,p, 'p')
end
hold off
plot (alpha,p, 'p')
xlabel('\alpha')
ylabel('p')
Plot after the loop: 
alpha=0:0.2:2*pi;
for k = 1:numel(alpha)
  p(k) = (p_m*sqrt(1-c^2))/(1-c*cos(alpha(k)-delta));
end
figure
plot (alpha,p, '-p')
xlabel('\alpha')
ylabel('p')
Make appropriate changes to get the result you want.
Before the plot loop (everything up to and including the ‘delta’ assignment), your code is unchanged.
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