Drag equationIn fluid dynamics, the drag equation is a formula used to calculate the force of drag experienced by an object due to movement through a fully enclosing fluid.
Drag (physics)In fluid dynamics, drag, sometimes referred to as fluid resistance, and also known as viscous force, is a force acting opposite to the direction of motion of any object moving with respect to a surrounding fluid. This can exist between two fluid layers, or between a fluid and a solid surface. Drag forces tend to decrease fluid velocity relative to the solid object in the fluid's path. Unlike other resistive forces, drag force depends on velocity.
Flow velocityIn continuum mechanics the flow velocity in fluid dynamics, also macroscopic velocity in statistical mechanics, or drift velocity in electromagnetism, is a vector field used to mathematically describe the motion of a continuum. The length of the flow velocity vector is scalar, the flow speed. It is also called velocity field; when evaluated along a line, it is called a velocity profile (as in, e.g., law of the wall).
Fluid dynamicsAspects of fluid mechanics involving fluid flow Computer generated animation of fluid in a tube flowing past a cylinder, showing the shedding of a series of vortices in the flow behind it, called a von Kármán vortex street.
Skin friction dragType of aerodynamic or hydrodynamic drag Skin friction drag or viscous drag is a type of aerodynamic or hydrodynamic drag, which is resistant force exerted on an object moving in a fluid. Skin friction drag is caused by the viscosity of fluids and develops from laminar to turbulent drag as a fluid moves more rapidly across the surface of an object.
AirfoilAn airfoil (American English) or aerofoil (British English) is a streamlined body that is capable of generating significantly more lift than drag. Wings, sails and propeller blades are examples of airfoils. Foils which work in a similar way submerged in water are called hydrofoils. When oriented at a suitable angle, a solid body moving through a fluid deflects the passing fluid, resulting in a force on the airfoil in the direction opposite to the deflection.
Parasitic dragParasitic drag, also known as profile drag, is a type of aerodynamic drag that acts on any object when the object is moving through a fluid. Parasitic drag is defined as the combination of form drag and skin friction drag. It is named as such because it is not useful, in contrast with lift-induced drag which is created when an airfoil generates lift. All objects experience parasitic drag, regardless of whether they generate lift.
HydrofoilA hydrofoil is a lifting surface, or foil, that operates in water. It is similar in appearance and purpose to aerofoils used by airplanes. Boats that use hydrofoil technology are also simply termed hydrofoils. As a craft gains speed, the hydrofoils lift the boat's hull out of the water, decreasing drag and allowing greater speeds.
Dimensionless quantityDimensionless quantities, or quantities of dimension one, are quantities with no associated units of measurement. These may be ratios of quantities with the same physical units or ratios of dimensionally equal products with identical units. For instance, alcohol by volume (ABV) represents a volumetric ratio; its value remains independent of the specific units of volume used, such as in milliliters per milliliter (mL/mL).
AerodynamicsAerodynamics (from Ancient Greek ἀήρ (aḗr) 'air' and δυναμική (dunamikḗ) 'dynamics') is the study of the motion of air, particularly when affected by a solid object, such as an airplane wing. It involves topics covered in the field of fluid dynamics and its subfield of gas dynamics, and is an important domain of study in aeronautics.
Lift-induced dragLift-induced drag, induced drag, vortex drag, or sometimes drag due to lift, in aerodynamics, is an aerodynamic drag force that occurs whenever a moving object redirects the airflow coming at it. This drag force occurs in airplanes due to wings or a lifting body redirecting air to cause lift and also in cars with airfoil wings that redirect air to cause a downforce.*As an Amazon Associate I earn from qualifying purchases.