How does drag coefficient change with altitude?

In summary, the Reynolds-Number decreases with an increasing altitude, which means that drag increases with an increasing altitude – assuming velocity and reference length are constant.

Does drag coefficient decrease with velocity?

Drag force is proportional to the velocity for low-speed flow and the squared velocity for high speed flow, where the distinction between low and high speed is measured by the Reynolds number. Drag forces always tend to decrease fluid velocity relative to the solid object in the fluid’s path.

Does drag coefficient increase with velocity?

Drag increases with speed (v). An object that is stationary with respect to the fluid will certainly not experience any drag force. Start moving and a resistive force will arise.

Does drag coefficient change with area?

The drag coefficient is always associated with a particular surface area. The drag coefficient of any object comprises the effects of the two basic contributors to fluid dynamic drag: skin friction and form drag.

Why does drag decrease with altitude?

Lift and drag depend linearly on the density of the fluid. Halving the density halves the lift, halving the density halves the drag. In the atmosphere, air density decreases as altitude increases. This explains why airplanes have a flight ceiling, an altitude above which it cannot fly.

Why does lift decrease when altitude increases?

The physical quantity which actually affects the lift as we change altitude is the air density. Air density itself decreases with altitude; and it is this decrease which causes the lift to drop.

What changes the coefficient of drag?

Properties of the Air Drag depends directly on the mass of the flow going past the aircraft. The drag also depends in a complex way on two other properties of the air: its viscosity and its compressibility. These factors affect the wave drag and skin friction which are described above.

What affects the drag coefficient?

Some factors that impact the magnitude of air resistance (drag) include the size and shape of the object, the velocity of the object and the air, and other properties of the air such as its viscosity, mass, and compressibility.

Does minimum drag vary with altitude?

The airspeed at which this occurs is called the minimum drag airspeed, and the associated lift coefficient, the lift coefficient for minimum drag. We can note from the figure that the minimum drag is the same at all altitudes, but the minimum drag speed increases with altitude.

Does lift drag ratio change with altitude?

Actually aerodynamic drag stays the same when altitude is increased. To explain this phenomena we’ll first have a look how speed is measured in an aircraft and thereafter we’ll have look at lift and drag.

Does altitude affect lift coefficient?

Lift changes with altitude, but there is more to it than just the height above sea level. The physical quantity which actually affects the lift as we change altitude is the air density. Air density itself decreases with altitude; and it is this decrease which causes the lift to drop.