Code for equation with ln

How can i Code it?

u=0.23 y=0.3 v=0.00001

u/u’=5*log(u’*y/v)-3.05

u’=?

I need to find the value of u’.

Answer 1

[Star Strider]

Try this:

u=0.23; 
y=0.3; 
v=0.00001;

fcn = @(ustar,u,y,nu) 5*log(ustar.*y/nu)- 3.05 - u/ustar;

ustar = fsolve(@(ustar)fcn(ustar,u,y,v), 1)

ustar =
       0.00918407730971717

[Sayeed]

It is somehow not working to my matlab. Can you please send me the code file with attachment?

[Star Strider]

I already posted all the code that is needed to solve this problem.

You need to have the Optimization Toolbox installed to use fsolve.

You will have fminsearch regardless, so try using fminsearch on the norm of ‘fcn’:

ustar = fminsearch(@(ustar)norm(fcn(ustar,u,y,v)), 1)

ustar =
             0.00918426513671787