Αποτελέσματα Αναζήτησης
Drag is the friction from fluids like air and water. A runner feels the force of aerodynamic drag. A swimmer feels the force of hydrodynamic drag.
Air friction, or air drag, is an example of fluid friction. Unlike the standard model of surface friction, such friction forces are velocity dependent. The velocity dependence may be very complicated, and only special cases can be treated analytically.
For aircraft, pressure and friction drag are included in the definition of parasitic drag. Parasite drag is often expressed in terms of a hypothetical. Parasitic drag experienced by aircraft. This is the area of a flat plate perpendicular to the flow.
20 Οκτ 2022 · The field of automotive aerodynamics involves examining the airflow around a vehicle. The goal is to diminish drag and wind noise and avoid unintended lift forces contributing to aerodynamic instability, particularly at high speeds.
Aerodynamic drag force. Using equation (2) and data from the tables above, we can plot the aerodynamic drag force for vehicle speeds between 0 and 250 kph. Image: Aerodynamic drag force for several vehicles. The aero drag force increases with the square of the vehicle speed.
As the vehicle moves forwards through the air the air rushes past the vehicle. This causes friction, which we call drag, and this slows the vehicle down. Large amounts of money are spent by the designers of cars to try and make a car which has a little drag as possible.
At highway speeds, over 50% of the power of a car is used to overcome air drag. The most fuel-efficient cruising speed is about 70–80 km/h (about 45–50 mi/h). For this reason, during the 1970s oil crisis in the United States, maximum speeds on highways were set at about 90 km/h (55 mi/h).
