I want to combine to plot . Pressure history time not start up versus time and transient and final versus time. cann someone helps me thank you. I want one plot that arrange everything

R=8.314/32;

T0=2930;

a=(12)/((2.027*10^6)^0.45);

rhoP=1920;

Astar=pi*0.25^2;

k=1.35;

n=0.45;

P0=101325;

P = P0;

%syms P(t)

%at beginning of the integration set initial values for the persistent variables

rp=0.35; %initial port radius

t1=0; %initial time step

rhoO=P/(R*T0); %gas density

rp=min(rp+((a*P^n)*10^-3)*(t1-t1),0.7);

Ab=2*pi*rp*8;%burn area

v0 = 0.1;

dP=@(t,P)Fun(t,P,R,T0,rp,a,n,t1,Ab,rhoP,Astar,k,v0);%@(t,P)(Ab.*a.*P.^n.*(rhoP-rhoO)-P.*Astar.*sqrt(k/(R.*T0)).*(2/(k+1)).^((k+1)/(2.*(k-1)))).*R.*T0./v0;

[t,P]=ode45(dP, [0,0.1],P0);

y = P;

figure(1)

plot(t,y)

xlabel("Time (s)")

ylabel("Chamber Pressure (Pa)")

title("Chamber Pressure vs Time (Start-Up)")

[t,P]=ode45(dP,[0,60],P0); %numerically integrates dP/dt and returns time step and the pressure at that time step

figure(2)

plot(t,y)

xlabel("Time (s)")

ylabel("Chamber Pressure (Pa)")

title("Chamber Pressure vs Time")

function dP = Fun(t,P,R,T0,rp,a,n,t1,rhoP,Astar,k)

rhoO=P/(R*T0); %gas density

if t==0 %at beginning of the integration set initial values for the persistent variables

rp=0.35; %initial port radius

t1=0; %initial time step

end

rp=min(rp+((a*P^n)*10^-3)*(t-t1),0.7);

Ab=2*pi*rp*8;%burn area

if rp>=0.7 %if grain gets exhausted

Ab=0; %burn area =0

end

v0=pi*rp^2*8; %recalculating free volume available in chamber

t1=t;

dP = (Ab.*a.*P.^n.*(rhoP-rhoO)-P.*Astar.*sqrt(k/(R.*T0)).*(2/(k+1)).^((k+1)/(2.*(k-1)))).*R.*T0./v0;

end

Error in HW08A (line 20)

[t,P]=ode45(dP, [0,0.1],P0);

I want to combine to plot . Pressure history time not start up versus time and transient and final versus time. cann someone helps me thank you.

I want one plot that arrange everyting

Answer 1

[Image Analyst]

To combine plots on one plot with the same scale (units), use hold on

plot(x1, y1)
hold on
plot(x2,y2);

To use different y axes, try plotyy() or yyaxis().