JosiahEnrico

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Josiah Enrico Syefatiawan

Holaaa

Perkenalkan nama saya Josiah Enrico S dari jurusan teknik mesin FTUI. Sebagai salah seorang mahasiswa, saya senang belajar dan berbagi banyak hal baru kepada dunia. Melalui wiki ini, saya akan berbagi kepada kalian tentang apa yang saya pelajari. :)

Aplikasi Modelica - Metode Numerik/18 November 2020

Berikut ini adalah contoh penerapan aplikasi OpenModelica untuk membuat 4 algoritma metode numerik dalam mencari roots of equation (akar persamaan) dari:

f(x) = exp^(-x)-(x)

f'(x) = -exp^(-x)-1

error maksimum = 0.0000001

1) Newton Raphson (Terbuka)
model Newton_Raphson_Algorithm

parameter Real g=1; //guess
parameter Integer N=20; //max iteration
parameter Real er=0.0000001; //error maximum
Real a[N]; 
Real y[N];//function
Real ER[N]; //error
Real sol; //solution

algorithm

a[1]:=g;
y[1]:=a[1]-(exp(-a[1])-a[1])/(-exp(-a[1])-1);
ER[1]:=abs(1-a[1]/y[1]);

for i in 2:N loop
  a[i]:=y[i-1];
  y[i]:=a[i]-(exp(-a[i])-a[i])/(-exp(-a[i])-1);
  ER[i]:=abs(1-y[i-1]/y[i]);

  if ER[i]<er then
 sol:=y[i];
 break;
 end if;
end for;

end Newton_Raphson_Algorithm;
2) Secant (Terbuka)
model Secant_Algorithm

parameter Real a=0; //guess
parameter Real b=1; //guess
parameter Integer N=10; //max iteration
parameter Real er=0.0000001; //error maximum
Real A[N];
Real B[N];
Real y[N];
Real ER[N];
Real sol; //solution

algorithm

A[1]:=a;
B[1]:=b;
y[1]:=B[1]-(exp(-B[1])-B[1])*(A[1]-B[1])/((exp(-A[1])-A[1])-(exp(-B[1])-B[1]));
ER[1]:=abs(1-B[1]/y[1]);

for i in 2:N loop
 A[i]:=B[i-1];
 B[i]:=y[i-1];
 y[i]:=B[i]-(exp(-B[i])-B[i])*(A[i]-B[i])/((exp(-A[i])-A[i])-(exp(-B[i])-B[i]));
 ER[i]:=abs(1-y[i-1]/y[i]);

 if ER[i]<er then
 sol:=y[i];
 break;
 
 end if;
end for;

end Secant_Algorithm;
3) Bisection (Tertutup)
model Bisection_Algorithm

parameter Real a=0; //guess bawah
parameter Real b=1; //guess atas
parameter Integer N=50; //max iteration
parameter Real er=0.0000001; //error maximum
Real fa=(exp(-a)-a);
Real fb=(exp(-b)-b);
Real A[N];
Real B[N];
Real fy[N];
Real y[N];
Real ER[N];
Real sol; //solution

algorithm

if fa*fb<0 then

A[1]:=a;
B[1]:=b;
y[1]:=(A[1]+B[1])/2;
fy[1]:=exp(-y[1])-y[1];
ER[1]:=1;

for i in 2:N loop
 if fy[i-1]>0 then
 A[i]:=y[i-1];
 B[i]:=B[i-1];
 else
 A[i]:=A[i-1];
 B[i]:=y[i-1];
 end if;
   
 y[i]:=(A[i]+ B[i])/2;
 fy[i]:=exp(-y[i])-y[i];
 ER[i]:=abs(1-y[i-1]/y[i]);
 
 if ER[i]<er then
 sol:=y[i];
 break;
 end if;

end for;
end if;

end Bisection_Algorithm;

3) Regula Falsi (Tertutup)
model Regula_Falsi_Algorithm

parameter Real a=0; //guess bawah
parameter Real b=1; //guess atas
parameter Integer N=20; //max iteration
parameter Real er=0.0000001; //error maximum
Real A[N];
Real B[N];
Real fa[N];
Real fb[N];
Real fy[N];
Real y[N];
Real ER[N];
Real sol; //solution

algorithm

A[1]:=a;
B[1]:=b;
fa[1]:=exp(-A[1])-A[1];
fb[1]:=exp(-B[1])-B[1]; 

if fa[1]*fb[1]<0 then 

y[1]:=(A[1]*fb[1]-B[1]*fa[1])/(fb[1]-fa[1]);
fy[1]:=exp(-y[1])-y[1];
ER[1]:=1; 

for i in 2:N loop
 if fy[i-1]>0 then
 A[i]:=y[i-1];
 B[i]:=B[i-1];
 else
 A[i]:=A[i-1];
 B[i]:=y[i-1];
 end if;
 
 fa[i]:=exp(-A[i])-A[i];
 fb[i]:=exp(-B[i])-B[i];
 y[i]:=(A[i]*fb[i]-B[i]*fa[i])/(fb[i]-fa[i]);
 fy[i]:=exp(-y[i])-y[i];
 ER[i]:=abs(1-y[i-1]/y[i]);
 
 if ER[i]<er then
 sol:=y[i];
 break;
 end if;
end for;
end if;
 
end Regula_Falsi_Algorithm;



Gate Valve - Aplikasi CFD/12 November 2020

Gate Valve

membuka atau menutup aliran

Mengatur kecepataan fluida (Regulasi)

Mangatasi Backflow atau aliran balik