How to plot Mach Number Contours
40 visualizaciones (últimos 30 días)
Mostrar comentarios más antiguos
Bamelari Jovani
el 22 de Ag. de 2024 a las 13:16
Comentada: Voss
el 22 de Ag. de 2024 a las 16:56
Greetings everyone, below is the code which generates the diverging portion of a supersonic nozzle using the Method Of Characteristics. How can I plot the Mach Number contours within the same plot along with a colorbar? The plot which I want is attached below(plot.png) Thank you!
plot.png reference: https://doi.org/10.1063/5.0150327
I have attached the function files.
PMF = Calculates the prandtl meyer angle, mach angle and Mach Number
Arc = Generates the circular arc for the expansion region of nozzle(Region where the lines emanate)
%% Initialize datapoint matrices
clear
G=1.4;
Me = 2;
n = 55;
display = 1;
Km = zeros(n,n); % K- vlaues (Constant along right running characteristic lines)
Kp = zeros(n,n); % K+ vlaues (Constant along left running characteristic lines)
Theta = zeros(n,n); % Flow angles relative to the horizontal
Mu = zeros(n,n); % Mach angles
M = zeros(n,n); % Mach Numbers
x = zeros(n,n); % x-coordinates
y = zeros(n,n); % y-coordinates
%% Generate the contraction region using a 3rd order polynomial. Do not run this
%{
R = 287;
T0 = 300;
% Define the mach number in contraction region
uu = 25.0; %velocity in contraction region
a = sqrt(G*R*T0 - 0.5*(G-1)*uu^2); % local speed of sound
Mconv = uu/a; % Mach number
% Calculate the area ratio of contraction region
[~,~,~,~,area] = flowisentropic(G,Mconv); % area ratio
% Inlet convergent section geometry
y0 =1;
H_in = area * y0;
L_e = 1.5; %(1.0/3.0)*xwall(end);
%
[xconv,yconv] = Convergent_3rd(G,y0,H_in,L_e,n);
%}
%% Generate the convergent portion of a nozzle
% The inlet height/area and exit height/area(divergent) are same
% Therefore we have same A/A* = 1.6875
% Corresponding to Mach = 0.3722
%% Find NuMax (maximum expansion angle)
[~, NuMax, ~] = PMF(G,Me,0,0);
ThetaMax = NuMax/2;
%% Define some flow parameters of originating characteristic lines
dT = ThetaMax/n;
ThetaArc(:,1) = (0:dT:ThetaMax);
NuArc = ThetaArc;
KmArc = ThetaArc + NuArc;
[~, ~, MuArc(:,1)] = PMF(G,0,NuArc(:,1),0);
%% Coordinates of wall along curve from throat
y0 = 1; % Define throat half-height
ThroatCurveRadius = 1.5*y0; % Radius of curvature just downstream of the throat
% for larger factors, ywall deviates from A/A* preferred value is 1.1
%L_e = 1.1 * y0 * sind(ThetaMax);
[xarc, yarc] = Arc(ThroatCurveRadius,ThetaArc); % Finds x- and y-coordinates for given theta-values
yarc(:,1) = yarc(:,1) + y0; % Defines offset due to arc being above horizontal
%% Fill in missing datapoint info along first C+ line
% First centerline datapoint done manually
Km(:,1) = KmArc(2:length(KmArc),1);
Theta(:,1) = ThetaArc(2:length(KmArc),1);
Nu(:,1) = Theta(:,1);
Kp(:,1) = Theta(:,1)-Nu(:,1);
M(1,1) = 1.0;
Nu(1,1) = 0;
Mu(1,1) = 90;
y(1,1) = 0;
x(1,1) = xarc(2,1) + (y(1,1) - yarc(2,1))/tand((ThetaArc(2,1) - MuArc(2,1) - MuArc(2,1))/2);
% Finds the information at interior nodes along first C+ line
for i=2:n
[M(i,1), Nu(i,1), Mu(i,1)] = PMF(G,0,Nu(i,1),0);
s1 = tand((ThetaArc(i+1,1) - MuArc(i+1,1) + Theta(i,1) - Mu(i,1))/2);
s2 = tand((Theta(i-1,1) + Mu(i-1,1) + Theta(i,1) + Mu(i,1))/2);
x(i,1) = ((y(i-1,1)-x(i-1,1)*s2)-(yarc(i+1,1)-xarc(i+1,1)*s1))/(s1-s2);
y(i,1) = y(i-1,1) + (x(i,1)-x(i-1,1))*s2;
end
%% Find flow properties at remaining interior nodes
for j=2:n;
for i=1:n+1-j;
Km(i,j) = Km(i+1,j-1);
if i==1;
Theta(i,j) = 0;
Kp(i,j) = -Km(i,j);
Nu(i,j) = Km(i,j);
[M(i,j), Nu(i,j), Mu(i,j)] = PMF(G,0,Nu(i,j),0);
s1 = tand((Theta(i+1,j-1)-Mu(i+1,j-1)+Theta(i,j)-Mu(i,j))/2);
x(i,j) = x(i+1,j-1) - y(i+1,j-1)/s1;
y(i,j) = 0;
else
Kp(i,j) = Kp(i-1,j);
Theta(i,j) = (Km(i,j)+Kp(i,j))/2;
Nu(i,j) = (Km(i,j)-Kp(i,j))/2;
[M(i,j), Nu(i,j), Mu(i,j)] = PMF(G,0,Nu(i,j),0);
s1 = tand((Theta(i+1,j-1)-Mu(i+1,j-1)+Theta(i,j)-Mu(i,j))/2);
s2 = tand((Theta(i-1,j)+Mu(i-1,j)+Theta(i,j)+Mu(i,j))/2);
x(i,j) = ((y(i-1,j)-x(i-1,j)*s2)-(y(i+1,j-1)-x(i+1,j-1)*s1))/(s1-s2);
y(i,j) = y(i-1,j) + (x(i,j)-x(i-1,j))*s2;
end
end
end
%% Find wall node information
xwall = zeros(2*n,1);
ywall = xwall;
ThetaWall = ywall;
xwall(1:n,1) = xarc(2:length(xarc),1);
ywall(1:n,1) = yarc(2:length(xarc),1);
ThetaWall(1:n,1) = ThetaArc(2:length(xarc),1);
for i=1:n-1
ThetaWall(n+i,1) = ThetaWall(n-i,1);
end
for i=1:n
s1 = tand((ThetaWall(n+i-1,1) + ThetaWall(n+i,1))/2);
s2 = tand(Theta(n+1-i,i)+Mu(n+1-i,i));
xwall(n+i,1) = ((y(n+1-i,i)-x(n+1-i,i)*s2)-(ywall(n+i-1,1)-xwall(n+i-1,1)*s1))/(s1-s2);
ywall(n+i,1) = ywall(n+i-1,1) + (xwall(n+i,1)-xwall(n+i-1,1))*s1;
end
%% Provide wall geometry to user
assignin('caller','xwall',xwall)
assignin('caller','ywall',ywall)
assignin('caller','Coords',[xwall ywall])
%%
% Draw contour and characteristic web
if display == 1
plot(xwall,ywall,'-')
axis equal
axis([0 ceil(xwall(length(xwall),1)) 0 ceil(ywall(length(ywall),1))])
hold on
plot(xarc,yarc,'k-')
for i=1:n-1
plot(x(1:n+1-i,i),y(1:n+1-i,i))
end
for i=1:n
plot([xarc(i,1) x(i,1)],[yarc(i,1) y(i,1)])
plot([x(n+1-i,i) xwall(i+n,1)],[y(n+1-i,i) ywall(i+n,1)])
end
for c=1:n
for r=2:n+1-c
plot([x(c,r) x(c+1,r-1)],[y(c,r) y(c+1,r-1)])
end
end
xlabel('Length [x/y0]')
ylabel('Height [y/y0]')
end
4 comentarios
Cris LaPierre
el 22 de Ag. de 2024 a las 13:57
Editada: Cris LaPierre
el 22 de Ag. de 2024 a las 13:59
Thank you. When I ran the code, I discovered that Convergent_new_3rd is also missing. Once you attach everything, click the green play button in the toolstrip to execute the code. If nothing is missing, your code should run without error.
Respuestas (1)
Voss
el 22 de Ag. de 2024 a las 16:21
Adding the line
contourf(x,y,M)
to the end of your code produces the following result:
%% Initialize datapoint matrices
clear
G=1.4;
Me = 2;
n = 55;
display = 1;
Km = zeros(n,n); % K- vlaues (Constant along right running characteristic lines)
Kp = zeros(n,n); % K+ vlaues (Constant along left running characteristic lines)
Theta = zeros(n,n); % Flow angles relative to the horizontal
Mu = zeros(n,n); % Mach angles
M = zeros(n,n); % Mach Numbers
x = zeros(n,n); % x-coordinates
y = zeros(n,n); % y-coordinates
%% Generate the contraction region using a 3rd order polynomial. Do not run this
%{
R = 287;
T0 = 300;
% Define the mach number in contraction region
uu = 25.0; %velocity in contraction region
a = sqrt(G*R*T0 - 0.5*(G-1)*uu^2); % local speed of sound
Mconv = uu/a; % Mach number
% Calculate the area ratio of contraction region
[~,~,~,~,area] = flowisentropic(G,Mconv); % area ratio
% Inlet convergent section geometry
y0 =1;
H_in = area * y0;
L_e = 1.5; %(1.0/3.0)*xwall(end);
%
[xconv,yconv] = Convergent_3rd(G,y0,H_in,L_e,n);
%}
%% Generate the convergent portion of a nozzle
% The inlet height/area and exit height/area(divergent) are same
% Therefore we have same A/A* = 1.6875
% Corresponding to Mach = 0.3722
%% Find NuMax (maximum expansion angle)
[~, NuMax, ~] = PMF(G,Me,0,0);
ThetaMax = NuMax/2;
%% Define some flow parameters of originating characteristic lines
dT = ThetaMax/n;
ThetaArc(:,1) = (0:dT:ThetaMax);
NuArc = ThetaArc;
KmArc = ThetaArc + NuArc;
[~, ~, MuArc(:,1)] = PMF(G,0,NuArc(:,1),0);
%% Coordinates of wall along curve from throat
y0 = 1; % Define throat half-height
ThroatCurveRadius = 1.5*y0; % Radius of curvature just downstream of the throat
% for larger factors, ywall deviates from A/A* preferred value is 1.1
%L_e = 1.1 * y0 * sind(ThetaMax);
[xarc, yarc] = Arc(ThroatCurveRadius,ThetaArc); % Finds x- and y-coordinates for given theta-values
yarc(:,1) = yarc(:,1) + y0; % Defines offset due to arc being above horizontal
%% Fill in missing datapoint info along first C+ line
% First centerline datapoint done manually
Km(:,1) = KmArc(2:length(KmArc),1);
Theta(:,1) = ThetaArc(2:length(KmArc),1);
Nu(:,1) = Theta(:,1);
Kp(:,1) = Theta(:,1)-Nu(:,1);
M(1,1) = 1.0;
Nu(1,1) = 0;
Mu(1,1) = 90;
y(1,1) = 0;
x(1,1) = xarc(2,1) + (y(1,1) - yarc(2,1))/tand((ThetaArc(2,1) - MuArc(2,1) - MuArc(2,1))/2);
% Finds the information at interior nodes along first C+ line
for i=2:n
[M(i,1), Nu(i,1), Mu(i,1)] = PMF(G,0,Nu(i,1),0);
s1 = tand((ThetaArc(i+1,1) - MuArc(i+1,1) + Theta(i,1) - Mu(i,1))/2);
s2 = tand((Theta(i-1,1) + Mu(i-1,1) + Theta(i,1) + Mu(i,1))/2);
x(i,1) = ((y(i-1,1)-x(i-1,1)*s2)-(yarc(i+1,1)-xarc(i+1,1)*s1))/(s1-s2);
y(i,1) = y(i-1,1) + (x(i,1)-x(i-1,1))*s2;
end
%% Find flow properties at remaining interior nodes
for j=2:n;
for i=1:n+1-j;
Km(i,j) = Km(i+1,j-1);
if i==1;
Theta(i,j) = 0;
Kp(i,j) = -Km(i,j);
Nu(i,j) = Km(i,j);
[M(i,j), Nu(i,j), Mu(i,j)] = PMF(G,0,Nu(i,j),0);
s1 = tand((Theta(i+1,j-1)-Mu(i+1,j-1)+Theta(i,j)-Mu(i,j))/2);
x(i,j) = x(i+1,j-1) - y(i+1,j-1)/s1;
y(i,j) = 0;
else
Kp(i,j) = Kp(i-1,j);
Theta(i,j) = (Km(i,j)+Kp(i,j))/2;
Nu(i,j) = (Km(i,j)-Kp(i,j))/2;
[M(i,j), Nu(i,j), Mu(i,j)] = PMF(G,0,Nu(i,j),0);
s1 = tand((Theta(i+1,j-1)-Mu(i+1,j-1)+Theta(i,j)-Mu(i,j))/2);
s2 = tand((Theta(i-1,j)+Mu(i-1,j)+Theta(i,j)+Mu(i,j))/2);
x(i,j) = ((y(i-1,j)-x(i-1,j)*s2)-(y(i+1,j-1)-x(i+1,j-1)*s1))/(s1-s2);
y(i,j) = y(i-1,j) + (x(i,j)-x(i-1,j))*s2;
end
end
end
%% Find wall node information
xwall = zeros(2*n,1);
ywall = xwall;
ThetaWall = ywall;
xwall(1:n,1) = xarc(2:length(xarc),1);
ywall(1:n,1) = yarc(2:length(xarc),1);
ThetaWall(1:n,1) = ThetaArc(2:length(xarc),1);
for i=1:n-1
ThetaWall(n+i,1) = ThetaWall(n-i,1);
end
for i=1:n
s1 = tand((ThetaWall(n+i-1,1) + ThetaWall(n+i,1))/2);
s2 = tand(Theta(n+1-i,i)+Mu(n+1-i,i));
xwall(n+i,1) = ((y(n+1-i,i)-x(n+1-i,i)*s2)-(ywall(n+i-1,1)-xwall(n+i-1,1)*s1))/(s1-s2);
ywall(n+i,1) = ywall(n+i-1,1) + (xwall(n+i,1)-xwall(n+i-1,1))*s1;
end
%% Provide wall geometry to user
assignin('caller','xwall',xwall)
assignin('caller','ywall',ywall)
assignin('caller','Coords',[xwall ywall])
%%
% Draw contour and characteristic web
if display == 1
plot(xwall,ywall,'-')
axis equal
axis([0 ceil(xwall(length(xwall),1)) 0 ceil(ywall(length(ywall),1))])
hold on
plot(xarc,yarc,'k-')
for i=1:n-1
plot(x(1:n+1-i,i),y(1:n+1-i,i))
end
for i=1:n
plot([xarc(i,1) x(i,1)],[yarc(i,1) y(i,1)])
plot([x(n+1-i,i) xwall(i+n,1)],[y(n+1-i,i) ywall(i+n,1)])
end
for c=1:n
for r=2:n+1-c
plot([x(c,r) x(c+1,r-1)],[y(c,r) y(c+1,r-1)])
end
end
xlabel('Length [x/y0]')
ylabel('Height [y/y0]')
end
contourf(x,y,M)
Is that what's intended?
2 comentarios
Voss
el 22 de Ag. de 2024 a las 16:56
OK, well that plot has no numbers on either axis, so what is it?
Ver también
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!