Looping for a specified number of iteration

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SITI AISHAH
SITI AISHAH am 6 Okt. 2019
clc
clear all
%-------------------------------------------------------------------------%
% Specify the variable %
oil_SAE = 10;
Temp_in = 85; % Sump Temperature (°C)
d = 0.15; % Shaft Journal Diameter (Meter, m)
r = (d/2); % Shaft Journal Radius (Meter, m)
N = (166.69/60); % Shaft Speed (revolution per second,rps)
W = 9000; % Radial Load (Newton, N)
L = 0.3; % Bearing Length (Meter, m)
c = 0.000026; % Bearing clearance (Meter,m)
%-------------------------------------------------------------------------%
% Calculate the variable %
C_ratio = r/c; % Clearance ratio
P = W/(d*L); % Nominal Pressure (Pascal)
Slenderness = L/d ; % Bearing Aspect Ratio
%-------------------------------------------------------------------------%
% Viscosity - Temperature Chart
Temperature = xlsread ('MFT','viscosity-temperature chart','A4:A30');
if oil_SAE == 10
V0 = 0.1089*10^(-3);
b = 1157.5 ;
elseif oil_SAE == 20
V0 = 0.0937*10^(-3);
b = 1271.6;
elseif oil_SAE == 30
V0 = 0.0971*10^(-3);
b = 1360.0;
elseif oil_SAE == 40
V0 = 0.0827*10^(-3);
b = 1474.4;
elseif oil_SAE == 50
V0 = 0.1171*10^(-3);
b = 1509.6;
elseif oil_SAE == 60
V0 = 0.1288*10^(-3);
b = 1564.0;
end
%-------------------------------------------------------------------------%
% Calculation to find average temperature and viscosity %
Tf = Temp_in + 3; % Assumed Average Temperature (°C)
V = V0*exp (b/((1.8*Tf)+127)); % Viscosity (Pa.s)
S = (C_ratio)^2*((V*N)/P); % Sommerfeld Number
if Slenderness == 1
delta_T = (0.349109 + (6.00940*S)+(0.047467*(S^2)))*(P*(10^-6))/0.120; % Temperature Rise(°C) at l/d=1
elseif Slenderness == 1/2
delta_T = (0.394552 + (6.392527*S)-(0.036013*(S^2)))*(P*(10^-6))/0.120; % Temperature Rise(°C) at l/d=1/2
elseif Slenderness == 1/4
delta_T = 0.933828 + (6.437512*S)- (0.011048*(S^2))*(P*(10^-6))/0.120; % Temperature Rise(°C) at l/d=1/4
else
delta_T = ((33405*(S)^6)-(51557*(S)^5)+(30669*(S)^4)-(8871.9*(S)^3)+(1297.4*(S)^2)-(85.088*(S))+2.6111)*(P*(10^-6))/0.120; % Temperature Rise(°C) at l/d=Infinity
end
T_average = Temp_in + (delta_T/2); % Average temperature (°C)
iter=0;
while iter <= 5 && abs (Tf-T_average)>0.001
iter = iter + 1;
delta = (Tf-T_average)/2;
Tf = Tf-delta;
V = V0*exp (b/((1.8*Tf)+127)); % Viscosity (Pa.s)
S = (C_ratio)^2*((V*N)/P); % Sommerfeld Number
if Slenderness == 1
delta_T = (0.349109 + (6.00940*S)+(0.047467*(S^2)))*(P*(10^-6))/0.120; % Temperature Rise(°C) at l/d=1
elseif Slenderness == 1/2
delta_T = (0.394552 + (6.392527*S)-(0.036013*(S^2)))*(P*(10^-6))/0.120; % Temperature Rise(°C) at l/d=1/2
elseif Slenderness == 1/4
delta_T = 0.933828 + (6.437512*S)- (0.011048*(S^2))*(P*(10^-6))/0.120; % Temperature Rise(°C) at l/d=1/4
else
delta_T = ((33405*(S)^6)-(51557*(S)^5)+(30669*(S)^4)-(8871.9*(S)^3)+(1297.4*(S)^2)-(85.088*(S))+2.6111)*(P*(10^-6))/0.120; % Temperature Rise(°C) at l/d=Infinity
end
T_average = Temp_in + (delta_T/2); % Average temperature (°C)
disp ('Table for iteration');disp (' c Tf V S deltaT T average ');
format shortG
disp ([c',Tf', V',S',delta_T', T_average'])
end
** I want to loop the iteration as long as Tf-T_average is not in negative value and also not more than 0.001 which is 0 for 5th iteration. If the 5th iteration this is still not satisfied, then I want to increase the c where c=c+0.000001 for the next iteration until Tf-T_average=0. Please help me.Thanks

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