How to Stop Whistling Noise of a Luggage Rack or Roof Bars

In order stop this annoying noise you have to disturb the airflow. One way to do it is to wrap a cord or rope around thr bars in s spiral manner.

A few meters of cord or rope at least 4mm thick

Connect the rope to one side of the bar or rack and wrap it around the bar to the other side. Do it with the front bar (or the front side of the rack) at least.