Air Drag
Air Drag - Related Videos
11:30
Buoyancy and Drag on Immersed Bodies
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2023
Source: Alexander S Rattner and Sanjay Adhikari; Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA Objects, vehicles, and organisms immersed in fluid mediums experience forces from the surrounding fluid in the form of buoyancy- a vertical upward force due to fluid weight, drag- a resistive force opposite the direction of motion, and lift- a force perpendicular to the direction of motion. Prediction and characterization of these forces is...
01:23
Drag
0 Views •
2025
Drag is a resistive force opposing an object’s motion through a fluid, resulting from surface pressure and shear forces. It comprises two components: a perpendicular one from pressure and a tangential one from shear stress. Accurate drag calculations use pressure and wall shear stress distributions, often determined through Computational Fluid Dynamics (CFD) or wind tunnel testing. The drag coefficient, a dimensionless measure, depends on factors like shape, Reynolds number, Mach number, Froude...
09:14
Paw-Dragging: a Novel, Sensitive Analysis of the Mouse Cylinder Test
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Cited by 53 •
2015
Classical forelimb asymmetry analysis of the cylinder test is routinely used to assess behavioural deficits in rats following brain injury or stroke; however, it fails to detect consistent deficits in mice. This study demonstrates that quantifying paw-dragging behaviour is a more sensitive analysis of brain injury in mice.
08:57
Cross Cylindrical Flow: Measuring Pressure Distribution and Estimating Drag Coefficients
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2023
Source: David Guo, College of Engineering, Technology, and Aeronautics (CETA), Southern New Hampshire University (SNHU), Manchester, New Hampshire The pressure distributions and drag estimations for cross cylindrical flow have been investigated for centuries. By ideal inviscid potential flow theory, the pressure distribution around a cylinder is vertically symmetric. The pressure distribution upstream and downstream of the cylinder is also symmetric, which results in a zero-net drag force.
01:18
Drag Force and Terminal Speed
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2023
An interesting force in everyday life is the force of drag on an object when it is moving in a fluid. Like friction, the drag force always opposes the motion of an object. Unlike simple friction, the drag force is proportional to some function of the velocity of the object in that fluid. This functionality is complicated and depends upon the shape of the object, its size, its velocity, and the fluid it is in. For most large objects, such as cyclists, cars, and baseballs, that are not moving too...
FAQs
As speed increases, air drag becomes more influential because the moving object interacts more strongly with the surrounding air. This changing resistance means the object does not maintain the same acceleration throughout its motion. In practical predictions, speed cannot be treated as an incidental detail; it is a central variable controlling how rapidly motion changes.
Object geometry changes the way air acts across the object. Cross-sectional area determines how much of the object faces the airflow, while shape affects the resulting pressure pattern. Surface characteristics also contribute through viscous friction, the resistance associated with air moving along the surface. These design variables help explain why differently shaped objects behave differently at similar speeds.
Terminal velocity is reached when the upward resistive force on a falling object balances the downward gravitational force. At that point, the forces no longer produce further acceleration, so the object continues falling at a steady speed. Air density, shape, area, surface characteristics, and speed all matter because they influence how quickly this balance is established.
To analyze a motion affected by air drag, identify the object’s speed, air density, shape, cross-sectional area, and surface characteristics, then consider how these factors alter resistance during the motion. Compare that resistance with the other relevant forces, such as gravity. This organized approach supports predictions about acceleration, travel, stopping, and whether terminal velocity can occur.
Air drag makes real motion differ from an idealized description that considers only gravity. For a falling body, resistance reduces the net force available to accelerate it; for a projectile, it changes how the object travels through the air. Consequently, predictions based on gravity alone may not capture the object’s acceleration, path, or eventual stopping behavior.
Vehicle and aircraft design must account for resistance because it affects predicted motion and energy use. Sports equipment can be shaped or configured with drag in mind, while parachutes depend on drag-related behavior to support safer descent. These applications translate the same physical principles into performance, control, and safety decisions.