[msbhatti123]

#include "udf.h"
#define YMIN 0.0 /* constants */
#define YMAX 600 /* max domain height*/
#define DELOVRH 0.5 /* fully turbulent at centre of pipe*/
#define uABL_star 0.745 /* friction velocity for particular angle*/
#define k 0.4 /* Von karman constant*/
#define y0 1.5 /* rougness length*/


/* profile for x-velocity */
DEFINE_PROFILE(x_velocity,t,i)

{
real y, del, h, x[ND_ND]; /* variable declarations */
face_t f;

h = YMAX - YMIN;
del = DELOVRH*h; /* it shows fully turbulent profile*/

begin_f_loop(f,t)

{

F_CENTROID(x,f,t);
y = x[1];

if (y <= del)
F_PROFILE(f,t,i) = ((uABL_star)/k)* ln ((y+y0/y);

else

F_PROFILE(f,t,i) = ((uABL_star)/k)* ln (((h-y)+y0/y);;


}
end_f_loop(f,t)


}



/* profile for kinetic energy */


DEFINE_PROFILE(k_profile,t,i)

{

real y, del, h, ufree, x[ND_ND];
real I, umean, σ ;

face_t f;

h = YMAX - YMIN;
del = DELOVRH*h;

I=σ/umean; /* umean =(( uABL star/k)*(ln((y+y0)/y))*/

begin_f_loop(f,t)

{

F_CENTROID(x,f,t);

y=x[1];

if (y <= del)

F_PROFILE(f,t,i)= (3/2)*[ σ/(( uABL star/k)*(ln((y+y0)/y))];

Else

F_PROFILE(f,t,i)= (3/2)*[ σ/(( uABL star/k)*(ln(((h-y)+y0)/(h-y)))];

}

end_f_loop(f,t)

}











/* profile for dissipation rate */


DEFINE_PROFILE(dissip_profile,t,i)

{

realω real y, x[ND_ND], del, h,real K, umean, real ε;

face_t f;

h = YMAX - YMIN;
del = DELOVRH*h;

ε=(uABL star)^3/k(y+y0);

begin_f_loop(f,t)

{

F_CENTROID(x,f,t);

y=x[1];

if (y <= del)

ω=[((uABL star)^3/k(y+y0))/[ (3/2)*[ σ/(( uABL star/k)*(ln((y+y0)/y))]];

else

ω=[((uABL star)^3/k((h-y)+y0))/[ (3/2)*[ σ/(( uABL star/k)*(ln(((h-y)+y0)/(h-y)))]];


}
end_f_loop(f,t)
}

[mprinkey]

You have double ;; on this line:

F_PROFILE(f,t,i) = ((uABL_star)/k)* ln (((h-y)+y0/y);;

ln isn't a math.h function. Natural Log is double log (double). Base-10 Log is double log10 (double);

I stopped looking after those. These are very simple errors. I recommend that you review basic C syntax and review how to interpret compiler errors for your particular compiler.