98 Computational Modelling in Hydraulic and Coastal Engineering
for m=1:nx
h6t(m)=h(m);
Q6t(m)=Q(m);
end
end
end
plot(1:nth,Qin,'k','Linewidth',1.5)
xlabel('Number of time steps x 2000 [s]')
ylabel('Inflow hydrograph [m^3/s]')
axis([0,15,0,660])
figure, plot(1:nx,Q1t,'b','Linewidth',1.5)
hold on
plot(1:nx,Q2t,'r','Linewidth',1.5)
plot(1:nx,Q3t,'g','Linewidth',1.5)
plot(1:nx,Q4t,'b--','Linewidth',1.5)
plot(1:nx,Q5t,'r--','Linewidth',1.5)
plot(1:nx,Q6t,'g--','Linewidth',1.5)
xlabel('Longitudinal distance x 1000 [m]')
ylabel('Water discharge [m^3/s]')
axis([0,42,0,550])
legend('t=1000*Dt','t=1500*Dt','t=2000*Dt','t=3000*Dt','t=45
00*Dt','t=9000*Dt')
figure, plot(1:nx,h1t,'b','Linewidth',1.5)
hold on
plot(1:nx,h2t,'r','Linewidth',1.5)
plot(1:nx,h3t,'g','Linewidth',1.5)
plot(1:nx,h4t,'b--','Linewidth',1.5)
plot(1:nx,h5t,'r--','Linewidth',1.5)
plot(1:nx,h6t,'g--','Linewidth',1.5)
xlabel('Longitudinal distance x 1000 [m]')
ylabel('Water depth [m]')
axis([0,42,0,2.6])
legend('t=1000*Dt','t=1500*Dt','t=2000*Dt','t=3000*Dt','t=45
00*Dt','t=9000*Dt')
PROBLEM 5.2
Solve the same problem by making the following suggested changes while
keeping the rest of the data constant:
1. Change the roughness coefficient linearly from C z = 105 m 1/2 /s at the
upstream boundary to C z = 30 m 1/2 /s at the downstream boundary.
Repeat the exercise by inverting the direction of roughness change
and compare the results.
2. For the upstream half length of the channel, set the slope to S o = 0.001
and for the downstream half to S o = 0.01. Check if there would be a
transition from subcritical to supercritical flow, run the program and
comment on the results.