Most recent value incremented variable from 'while' loop

Question

Riley Schmitt 2020-12-9

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/689059-most-recent-value-incremented-variable-from-while-loop

回答： Walter Roberson 2020-12-10

This code is meant to determine how low a cone will sink in water before the buoyancy force is equal to the weight of the cone. The buoyancy force is determined by summing the force on each area element and increasing the depth (increases the pressure) until the buoyancy force is equal to the weight of the cone. My code seems to be running ok as my while loop terminates when my "sumFz" is lower but similar in size to "'wCo", but when I go to retrieve the last 'z' (the depth) it just says it's zero. Can someone figure out why, please?

rhoFluid = 1000;
beta = 30*pi/180;
dtheta = pi/50;
mCo = 15;
wCo = g*mCo %Weight of cone
N = 100;
h = 0.5;
dz = h/N;
sumFz = wCo+1;
z = 0;
while sumFz <= wCo
    pressure = rhoFluid*g*z;
    for j = 1:N
        r = z*tan(beta);
        Fz(j) = pressure*1/2*r^2*dtheta*dz*cos(beta);
    end
    sumFz = sum(Fz,'all')   %Total buoancy force at current depth
    z = z+dz;
end
sum(Fz,'all')
z