Damage under car from hitting a tire on the freeway

Underneath the car on the passenger side is a plastic rubbery cover has come loose. It is about 2 ft long, less than a foot wide at the widest part it is between the wheel wells and appears to be just a cover for something or maybe there to reduce road noise. I think I can remove it and replace it myself, but don't know what to call it or where to order it. I don't think rubbery plastic thing is going to help me.