Knocking sound from the fender when making turn

[peterjaw]

Hi guys,
Recently, my car has weird knocking sound from the fender of the front tyre area.

When I make slow but sharp turn, like turning righ on a cross road or turning into the parking garage, if the road surface is bad or has pithole then I hear sort of knocking sound from the fender area; especially from the outter tyre area.

I don't always hear this but quite often. The sound is like a small thing hit the fender.

Does anyone have such an ecperience? Does anyone know what is this?