I am going to make it short and simple:
Can some one help me out to find the contact force per unit length.? Yes.
Is there any plot to find it out or need to do hand calculation ? Hand calculation.
If its hand calculation what will be the formula for it? F(force)/L(length).
If I understand your problem correctly - you have a curved surface that is applying force to a flat surface, is that it? If so, Siavash is wrong.
The above description is a Hertzian contact problem and those hand calculations may be found in reference books such as Roark's or there are some calculators online.
I have put in a problem to SW through our VAR because SW cannot analyze Hertzian (bearing) contact correctly. We have physical examples where SW FEA said everything was fine but the damage to the part was due to bearing loads.
I took a careful look at your screenshot, and it looks like you're doing work on an extruded rubber seal that contacts a door. Instead of simplifying this to a segment of the seal (as you've done, and for which Siavash Khajehhasani is of course correct) you should use 2D simplification with plane strain. Just set your length to 1, and all forces can then be interpreted as "force / unit length".