210 Computational Modelling in Hydraulic and Coastal Engineering
cmax(i,j)=cn(i,j);
end
end
end
index=k
end
[i,j]=meshgrid(1:1:nx,1:1:ny);
df1=fDep(:,3);
df2=reshape(df1,22,23);
df2=df2';
An=ones(size(df2));
idx=find(df2== 0);
An(idx)=0;
figure;
pcolor(An); hold on;
colormap(jet)
shading flat
i=1:nx;
j=1:ny;
Cplot=cmax(i,j);
contour(i,j,Cplot')
% colorbar('vert')
PROBLEM 8.2
Solve the same problem by making the suggested modifications while keeping the rest of the data constant:
1. Place the contaminant point source at location x = 16 km, y = 34 km.
2. The source ceases to pollute after 1440 minutes.
3. Replace the decay coefficient with a growth coefficient of the same rate.
4. Place two additional pollutant sources at locations (28 km, 20 km)
and (32 km, 16 km).
5. Change the time step to Δt = 120 min, 180 min and 240 min.
Run the simulations, compare the results and comment on the changes
observed regarding the spreading of the contaminant plume.
8.3 LAGRANGIAN MODELLING
OF MASS TRANSPORT
The hydrodynamic phenomena can be described by using either Lagrangian
or Eulerian methodology. The Lagrangian description (moving coordinates) uses the concept of the ‘system’. The system is always comprised of
the same group of fluid particles and the Lagrangian method traces the
movement of the system in time and space. The Eulerian description (fixed
coordinates) uses the concept of the ‘control volume’, a fixed volume in