How to perform Definite integral with respect to 1 variable on a function in 2 variables?

I am trying to evaluate the Froude Krylov Forces on vertical cyclinder

This Function has 2 variables s and theta, After integration I should get an expression in terms of 't'

which I get as,

Now I want to plot this function against 't'

So when I use fplot command, I get a blank graph

fplot(FK_f,[0,24])

the result i get is this

Can someone please suggest the solution for this?

[Torsten]

Convert FK_f into a function handle:

FK_fh = matlabFunction(FK_f)

[Akash Kumar]

Great!!

This works

Thanks :)