clc; clear; //Example 3.1 mu=10^-3 //N.s/m^2 //At distance y from surface //ux=a+by+cy^2+dy^3 //At y=0,ux=0 therefore a=0 //i.e tao=0 //At edge of boundary layer,ie y=del //ux=u_inf //At y=o,c=0 //At y=del,ux=b*del+d*del^3 //Therefore, b=-3*d*del^3 //d=-u_inf/(2*del^2) //b=3*u_inf/(2*del) //For velocity profile,we have: //del/x=4.64*(Nre_x)^(-1/2) //Evaluate N re_x x=75; //[mm] x=x/1000; //[m] u_inf=3; //[m/s] rho=1000 //[kg/m^3] for air Nre_x=u_inf*rho*x/mu //Reynold number //Substituting the value,we get del=x*4.64*(Nre_x^(-1/2)) //[m] printf("\nBoundary layer thickness is del=%f m or %f mm",del,del*1000); printf("\nWrong units in answer of book,m and mm are wrongly interchanged");