Pressure Drag
Pressure Drag - Related Videos
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.
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
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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.
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
Flow separation prevents the boundary layer from remaining attached to the surface as fluid moves around the body. This separated flow forms a low-pressure wake behind the object, increasing the pressure difference between regions on its surface. The resulting pressure imbalance raises resistance, so delaying separation and reducing the wake are central strategies for improving aerodynamic or hydrodynamic performance.
Shape and orientation control how fluid pressure changes as flow passes around an object. Configurations that encourage smoother flow and maintain boundary-layer attachment can limit the low-pressure region behind the body. In contrast, shapes or orientations that promote separation produce a larger wake and greater resistance. Engineers therefore evaluate geometry and alignment when developing efficient designs.
Pressure drag results from pressure differences associated with the body's shape, flow separation, and wake, whereas skin-friction drag is treated as a separate resistance component. Engineers analyze both because a design may reduce one without eliminating the other. Considering their combined effects gives a more complete basis for improving efficiency in aircraft, vehicles, pipelines, and other fluid-exposed structures.
Engineers can reduce pressure drag by streamlining a body, delaying boundary-layer separation, and shrinking the low-pressure wake. These changes modify the flow pattern around the surface rather than simply addressing resistance after it develops. Lower drag can reduce energy consumption and improve performance, making such strategies valuable when designing objects that move through air or water.
Pressure drag matters wherever fluid flows around a solid structure. Engineering examples identified for this analysis include aircraft, vehicles, buildings, pipelines, and underwater structures. The surrounding medium and operating geometry determine whether aerodynamic or hydrodynamic performance is the main concern, but the design objective remains similar: manage pressure changes, separation, and wake formation to limit resistance.
An engineering assessment can examine how geometry and orientation affect pressure changes, boundary-layer attachment, separation, and wake size. These flow features help indicate whether a proposed design will experience greater or lower resistance. The results support decisions aimed at improving aerodynamic or hydrodynamic performance, reducing energy consumption, and selecting more effective shapes for specific fluid-flow applications.