I am trying to import excel windspeed data and to multiply each table variables with the vectors within the for loop, how to change for table variables into vector form?

Question

Tzu-Tung Chen 2023-5-23

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1970689-i-am-trying-to-import-excel-windspeed-data-and-to-multiply-each-table-variables-with-the-vectors-wit

回答： Sugandhi 2023-6-7

clc; clear all; close all;
% Input data;
g = 9.81;
fs = 0.000003;
w_data = readtable("LakeTahoe_v2_wind_velocity_test.xlsx","ReadVariableNames",true);
%w_data only shows 11.2, 8.0, and 8.1
fi=0.001;
fb=0.05;
rdd=0.005;
ev=20.0;
huo=10.0;
hbo=10.0;
Dx=200.0;
Dt=10.0;
nx=50.0;
nt=103680.0;
% Initial conditions;
for k=1:nx-1
    hu(k)=huo;
    hb(k)=hbo;
    hun(k)=huo;
    hbn(k)=hbo;
end
for k1=1:nx
    zb(k1)=0;
    uu(k1)=0;
    ub(k1)=0;
    uun(k1)=0;
    ubn(k1)=0;
end
%I thought about adding another for loop here to run the main program below with the three different answers above
for i=1:nt
    % Continuity equation for the upper fluid layer;
    for j=2:nx-2
        qul(j)=uu(j)*(hu(j)+hu(j-1))/2;
        qur(j)=uu(j+1)*(hu(j)+hu(j+1))/2;
        hun(j)=hu(j)-(Dt/Dx)*(qur(j)-qul(j));
    end
    % Continuity equation for the lower fluid layer;
    for j=2:nx-2
        qbl(j)=ub(j)*(hb(j)+hb(j-1))/2;
        qbr(j)=ub(j+1)*(hb(j)+hb(j+1))/2;
        hbn(j)=hb(j)-(Dt/Dx)*(qbr(j)-qbl(j));
    end
    % Updating of layer depth values;
    for j=2:nx-2
        hu(j)=hun(j);
        hb(j)=hbn(j);
    end
    % Force equilibrium equation for the upper layer;
    for j=3:nx-2
        hum(j)=(hu(j)+hu(j-1))/2;
        ts(j)=fs*w.*abs(w)/hum(j); %wind velocity is here
        ti(j)=fi*(uu(j)-ub(j))*abs(uu(j)-ub(j))/hum(j);
        ed(j)=ev*(uu(j-1)-2*uu(j)+uu(j+1))/Dx^2;
        uun(j)=uu(j)-Dt*g*(hu(j)+hb(j)+zb(j)-hu(j-1)-hb(j-1)-zb(j-1))/Dx+Dt*(ed(j)+ts(j)-ti(j));
    end
    % Force equilibrium equation for the lower layer;
    for j=3:nx-2
        hbm(j)=(hb(j)+hb(j-1))/2;
        ti(j)=fi*(uu(j)-ub(j))*abs(uu(j)-ub(j))/hbm(j);
        tb(j)=fb*ub(j)*abs(ub(j))/hbm(j);
        ed(j)=ev*(ub(j-1)-2*ub(j)+ub(j+1))/Dx^2;
        ubn(j)=ub(j)-Dt*g*((hu(j)+hb(j)+zb(j)-hu(j-1)-hb(j-1)-zb(j-1))/Dx-rdd*(hu(j)-hu(j-1))/Dx)+Dt*(ed(j)+ti(j)-tb(j));
    end
    % Updating of fluid velocity values;
    for j=3:nx-2
        uu(j)=uun(j);
        ub(j)=ubn(j);
        Hbfinal(j)=hbn(j);
        Htotal(j)=hun(j)+hbn(j);
    end
    Eu=0;
    El=0;
    for j=3:nx-2
        Eu=Eu+(hu(j)+hu(j-1))/2*uu(j)^2;
        El=El+(hb(j)+hb(j-1))/2*ub(j)^2;
    end
    Hupper(i)=hu(nx-2);
    Hlower(i)=hb(nx-2);
end

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KSSV 2023-5-23

在 MATLAB Online 中打开

The below lines:

for k=1:nx-1
    hu(k)=huo;
    hb(k)=hbo;
    hun(k)=huo;
    hbn(k)=hbo;
end
for k1=1:nx
    zb(k1)=0;
    uu(k1)=0;
    ub(k1)=0;
    uun(k1)=0;
    ubn(k1)=0;
end

can be simply replaced by:

hu=huo*ones(1,nx-1);
hb=hbo*ones(1,nx-1);;
hun=huo*ones(1,nx-1);;
hbn=hbo*ones(1,nx-1);;
zb=zeros(1,nx) ;
uu=zeros(1,nx) ;
ub=zeros(1,nx) ;
uun=zeros(1,nx) ;
ubn=zeros(1,nx) ;

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Answer 1

Sugandhi 2023-6-7

在 MATLAB Online 中打开

Hi,

I understand that you want to convert table variables to vector form.

In MATLAB, you can convert a table variable to a vector using the table2array and reshape functions. Here's an example:

% Create a sample table
T = table(rand(3,1), rand(3,1), rand(3,1), 'VariableNames', {'Var1', 'Var2', 'Var3'})
T = 3×3 table
     Var1       Var2       Var3  
    _______    _______    _______

    0.74342    0.76146    0.16319
    0.54526    0.36217    0.86704
    0.88032    0.22428    0.99576
% Convert table to a numerical array
A = table2array(T)
A = 3×3
    0.7434    0.7615    0.1632
    0.5453    0.3622    0.8670
    0.8803    0.2243    0.9958
% Reshape array to column vector
v = reshape(A, numel(A), 1)
v = 9×1
    0.7434
    0.5453
    0.8803
    0.7615
    0.3622
    0.2243
    0.1632
    0.8670
    0.9958

In the code above, the `table` function is used to create a sample table with 3 rows and 3 variables. The `table2array` function is used to convert the table to a numerical array. The `reshape` function is then used to convert the array into a column vector.

For more understanding, kindly go through following links: