Calculate mean from for loop and plotting means for separate for loop

I need to plot average power against each KC value. Can anyone please help?

vector_of_KC_values=[2,4,6,8,10,12,14,16,18,20]
for column_number=1:length(vector_of_KC_values)
    KC=vector_of_KC_values(column_number)
    
    pi = acos(-1); % pi = 3.14159
    Um = 1; % Fluid Velicity amplitude
    D = 0.1; % cylinder diamter
    L = 1; % cylinder length
    m = 50; % cylinder mass
    rho = 1024; % fluid density
    K = 200; % spring stiffness
    c = 100; % damping constant
    CA = 1; % added mass coefficient
    CD = 1.8; % drag coefficient
    omega = 2*pi/T; % angular frequency of the flow
    md = rho*pi*(D*D)/4*L; % added mass
    Ap = D*L; % projected area
    T=(KC*D)/Um
    dt = T/40; % time step
    ndt = T/dt*10; % %total step to be calculated
    X(1:ndt+1) = 0; % save displacement X from step 0 to step ndt
    V(1:ndt+1) = 0;
    Power(1:ndt+1) = 0;
    time(1:ndt+1) = (0:ndt)*dt;
    for n=1:ndt
        % to calculate kx1 and kv1
        ta = time(n);
        aw = omega*Um*cos(omega*ta); % acceleration of the fluid
        Vw = Um*sin(omega*ta); % velocity of the fluid
        Va = V(n);
        Xa = X(n);
        t1 = CA*md*aw;
        t2 = 0.5*rho*CD*Ap*abs(Vw-Va)*(Vw-Va);
        t3 = -K*Xa-c*Va;
        kx1 = V(n);
        kv1 = (t1+t2+t3)/(m+CA*md);
        % to calculate kx2 and kv2
        ta = time(n)+dt/2;
        aw = omega*Um*cos(omega*ta); % acceleration of the fluid
        Vw = Um*sin(omega*ta); % velocity of the fluid
        Va = V(n)+0.5*dt*kv1;
        Xa = X(n)+0.5*dt*kx1;
        t1 = CA*md*aw;
        t2 = 0.5*rho*CD*Ap*abs(Vw-Va)*(Vw-Va);
        t3 = -K*Xa-c*Va;
        kx2 = V(n)+0.5*dt*kv1;
        kv2 = (t1+t2+t3)/(m+CA*md);
        % to calculate kx3 and kv3
        ta = time(n)+dt/2;
        aw = omega*Um*cos(omega*ta); % acceleration of the fluid
        Vw = Um*sin(omega*ta); % velocity of the fluid
        Va = V(n)+0.5*dt*kv2;
        Xa = X(n)+0.5*dt*kx2;
        t1 = CA*md*aw;
        t2 = 0.5*rho*CD*Ap*abs(Vw-Va)*(Vw-Va);
        t3 = -K*Xa-c*Va;
        kx3 = V(n)+0.5*dt*kv2;
        kv3 = (t1+t2+t3)/(m+CA*md);
        % to calculate kx4 and kv4
        ta = time(n)+dt;
        aw = omega*Um*cos(omega*ta); % acceleration of the fluid
        Vw = Um*sin(omega*ta); % velocity of the fluid
        Va = V(n)+0.5*dt*kv3;
        Xa = X(n)+0.5*dt*kx3;
        t1 = CA*md*aw;
        t2 = 0.5*rho*CD*Ap*abs(Vw-Va)*(Vw-Va);
        t3 = -K*Xa-c*Va;
        kx4 = V(n)+dt*kv3;
        kv4 = (t1+t2+t3)/(m+CA*md);
        % next step values
        X(n+1) = X(n)+(dt/6)*(kx1+2*kx2+2*kx3+kx4);
        V(n+1) = V(n)+(dt/6)*(kv1+2*kv2+2*kv3+kv4);
        Power(n+1)=c*V(n+1)^2;
    end
    Avg_power=mean(Power(n+1))
    figure (04);
    hold on
    plot(KC,Avg_power,'-r');
    xlabel(KC);
    ylabel('Average Power (W)'); 
    legend (Average Power for different KC values');
        hold off
    end

[Matt J]

Help with what? You've written a lot of code already.

Answer 1

[Star Strider]

There was an out-of-order statement (‘T’), no subscripting of the ‘Avg_power’ vector, and the wrong independent variable argument in the plot call. I also put the plot call outside the loops.

Try this —

vector_of_KC_values=[2,4,6,8,10,12,14,16,18,20]

vector_of_KC_values = 1×10

2 4 6 8 10 12 14 16 18 20

for column_number=1:length(vector_of_KC_values)
    KC=vector_of_KC_values(column_number)
pi = acos(-1); % pi = 3.14159
Um = 1; % Fluid Velicity amplitude
D = 0.1; % cylinder diamter
L = 1; % cylinder length
m = 50; % cylinder mass
rho = 1024; % fluid density
K = 200; % spring stiffness
c = 100; % damping constant
CA = 1; % added mass coefficient
CD = 1.8; % drag coefficient
T=(KC*D)/Um
omega = 2*pi/T; % angular frequency of the flow
md = rho*pi*(D*D)/4*L; % added mass
Ap = D*L; % projected area
% T=(KC*D)/Um
dt = T/40; % time step
ndt = T/dt*10; % %total step to be calculated
X(1:ndt+1) = 0; % save displacement X from step 0 to step ndt
V(1:ndt+1) = 0;
Power(1:ndt+1) = 0;
time(1:ndt+1) = (0:ndt)*dt;
for n=1:ndt
 % to calculate kx1 and kv1
 ta = time(n);
 aw = omega*Um*cos(omega*ta); % acceleration of the fluid
 Vw = Um*sin(omega*ta); % velocity of the fluid
 Va = V(n);
 Xa = X(n);
 t1 = CA*md*aw;
 t2 = 0.5*rho*CD*Ap*abs(Vw-Va)*(Vw-Va);
 t3 = -K*Xa-c*Va;
 kx1 = V(n);
 kv1 = (t1+t2+t3)/(m+CA*md);
 % to calculate kx2 and kv2
 ta = time(n)+dt/2;
 aw = omega*Um*cos(omega*ta); % acceleration of the fluid
 Vw = Um*sin(omega*ta); % velocity of the fluid
 Va = V(n)+0.5*dt*kv1;
 Xa = X(n)+0.5*dt*kx1;
 t1 = CA*md*aw;
 t2 = 0.5*rho*CD*Ap*abs(Vw-Va)*(Vw-Va);
 t3 = -K*Xa-c*Va;
 kx2 = V(n)+0.5*dt*kv1;
 kv2 = (t1+t2+t3)/(m+CA*md);
 % to calculate kx3 and kv3
 ta = time(n)+dt/2;
 aw = omega*Um*cos(omega*ta); % acceleration of the fluid
 Vw = Um*sin(omega*ta); % velocity of the fluid
 Va = V(n)+0.5*dt*kv2;
 Xa = X(n)+0.5*dt*kx2;
 t1 = CA*md*aw;
 t2 = 0.5*rho*CD*Ap*abs(Vw-Va)*(Vw-Va);
 t3 = -K*Xa-c*Va;
 kx3 = V(n)+0.5*dt*kv2;
 kv3 = (t1+t2+t3)/(m+CA*md);
 % to calculate kx4 and kv4
 ta = time(n)+dt;
 aw = omega*Um*cos(omega*ta); % acceleration of the fluid
 Vw = Um*sin(omega*ta); % velocity of the fluid
 Va = V(n)+0.5*dt*kv3;
 Xa = X(n)+0.5*dt*kx3;
 t1 = CA*md*aw;
 t2 = 0.5*rho*CD*Ap*abs(Vw-Va)*(Vw-Va);
 t3 = -K*Xa-c*Va;
 kx4 = V(n)+dt*kv3;
 kv4 = (t1+t2+t3)/(m+CA*md);
 % next step values
 X(n+1) = X(n)+(dt/6)*(kx1+2*kx2+2*kx3+kx4);
 V(n+1) = V(n)+(dt/6)*(kv1+2*kv2+2*kv3+kv4);
 Power(n+1)=c*V(n+1)^2;
end
Avg_power(column_number)=mean(Power(n+1));
end

KC = 2

T = 0.2000

KC = 4

T = 0.4000

KC = 6

T = 0.6000

KC = 8

T = 0.8000

KC = 10

T = 1

KC = 12

T = 1.2000

KC = 14

T = 1.4000

KC = 16

T = 1.6000

KC = 18

T = 1.8000

KC = 20

T = 2

figure (04);
hold on
plot(vector_of_KC_values,Avg_power,'.-r');
xlabel(KC);
ylabel('Average Power (W)'); 
legend ('Average Power for different KC values', 'Location','best');
hold off

.

[Ben Paul]

Works perfectly, thank you

[Star Strider]

My pleasure!

If my Answer helped you solve your problem, please Accept it!

.