read_dat_gravity.m

%Reads density and velocity .dat files from LB2D_Prime (select output of these in Flags.h) and
%plots head contours and velocity vectors when there is a gravitational
%acceleration

%Input file names and problem dimensions must be specified below.

clear all
close all

%Change to correct file
rho=load('rho34x198_frame0010_subs00_proc0000.dat')
p_vector=rho/3;
g=10^-4; %Use > 0 but assume pointed down

%Compute pressure heads
hp_vector=p_vector./(rho*g);

%Change to problem dimensions (rows = x_max, columns = y_max, both from
%file name)
rows=198
columns=34

%skip factor for plot to reduce plot density; use 1 for all points
rowskip=1
colskip=1

for j=1:columns
    j
    for i=1:rows

        hp(i,j)=hp_vector(j+(i-1)*columns);

        %Get rid of '0 pressure' solids that dominate pressure field
        if hp(i,j)==0
            hp(i,j)=NaN;
        end
   end
end
    
     
        
  
for j=1:columns
    j
    for i=1:rows
      
 %Set hp at top equal to zero and adjust others accordingly
hp(i,j)=hp(i,j)-hp(rows,j);   
        
        %Compute elevation head(assumes gravity pointed down and bottom row he = 0)
        
        he(i,j)=(i-1);
        
        
        %Add elevation head to get total head (assumes gravity pointed
        %down and bottom row he = 0)
        ht(i,j)=hp(i,j)+he(i,j);

    end
end

hold on
[C,H]=contour(ht(1:rowskip:rows,1:colskip:columns));
clabel(C,H);
[C1,H1]=contour(hp(1:rowskip:rows,1:colskip:columns));
clabel(C1,H1);
[C2,H2]=contour(he(1:rowskip:rows,1:colskip:columns));
clabel(C2,H2);

axis equal


%Change to correct file

uv_vector=load('u34x198_frame0010_subs00_proc0000.dat');


for j=1:columns
    j
    for i=1:rows
        u(i,j)=uv_vector(j+(i-1)*columns,1);  
        v(i,j)=uv_vector(j+(i-1)*columns,2);  

    end
end

hold on
quiver(u(1:rowskip:rows,1:colskip:columns),v(1:rowskip:rows,1:colskip:columns),5)


%This is for streamlines starting at y = rows from x = 1 to columns along the x axis. 
%Different geometries will require different starting points.

[Stream]= stream2(u,v,[1:columns],rows*ones(columns,1));
streamline(Stream)