Why is there wind when a car is moving?
3 Answers
Air exerts resistance on moving objects. This resistance is actually the reactive force from the air being pushed aside by the moving object. According to the law of conservation of momentum, the air instantly gains kinetic energy in the same direction as the moving object when being displaced. This means the air moves along with the object, and the movement of air constitutes what we perceive as wind. Driving precautions: Strictly adhere to traffic regulations, maintain proper steering control while driving, perform vehicle maintenance before departure, and exercise extra caution when driving at night as a beginner. Properly display the vehicle license plate, inspection sticker, insurance sticker, and always carry the vehicle registration certificate. Driving techniques: When meeting another vehicle at night, proactively switch to low beams and avoid using high beams to illuminate oncoming traffic. If blinded by high beams from an approaching vehicle and unable to see the road clearly, stop and wait until visibility is restored before proceeding.
This is actually a physical phenomenon caused by air flow. When you drive and move forward, the car displaces the air molecules in front of it, and this displaced air flows around the body of the car. Just like how you can feel the wind when you stick your hand out the window, the movement of the car turns the originally still air into flowing wind. The faster the car goes, the greater the force of displacing the air, and the stronger the sensation of wind. The wind at the front of the car also climbs up the windshield and escapes over the roof. I often observe this phenomenon on the highway, where the roof rack makes a whistling sound due to the pulling of the air flow. Additionally, if the window seals are aged, there can be a whistling sound from air leakage at high speeds.
As a car enthusiast, I understand this is an effect caused by relative motion. When the car moves forward, it essentially actively collides with the air, forcing the air to flow and create wind. This principle is somewhat similar to how airplane wings generate lift, except that the car's shape causes the airflow to mainly slide over its surface. This effect becomes particularly noticeable when windows are open, as the pressure difference between inside and outside the car forces wind into the cabin. Many sports cars adopt a fastback design to reduce this wind resistance, but ordinary family cars can hardly avoid it. I remember last time driving on a national highway, once the speed exceeded 60 km/h, I could hear the wind howling, and the roof even felt like it was being pressed downward by the airflow.
