Subject
Added mass, virtual mass and drag coefficients are shape factors that influence the resistance of bodies moving relative to a fluid in which they are immersed.
The drag coefficient (Cd) defines the effective resistance of a body due to its projected area and surface condition (quality)
The added mass coefficient (Ca) defines the additional fluid a body is expected to disturb
The virtual mass coefficient (Ci) defines the total mass of fluid a body is expected to disturb
The quality of the surface in contact with the fluid also influences these factors in that these coefficients increase with surface roughness. Whilst the general formulas used to define the above coefficients take surface quality into account, they do not account for the additional effects of highly pitted surfaces such as concrete and excessive corrosion.
Where such surfaces are exposed to turbulent flow conditions, the Colebrooke factor should be applied to the above coefficients (see Technical Help for methodology).
Added Drag calculates the drag, added mass and virtual mass coefficients for eight volumetric shapes such as long and short blocks, plates, cylinders and spheres and includes the proximity effects of a solid surface
The output data from Added Drag can be exported to CalQlata’s Fluid Forces calculator
For help using this calculator see Technical Help
Added Mass and Drag Calculator - Options
Long Prism (face): Calculates the shape coefficients of a long rectangular beam with the fluid flowing at right-angles to the axis of the beam against a flat face
Long Prism (corner): Calculates the shape coefficients of a long rectangular beam with the fluid flowing at right-angles to the axis of the beam against a corner
Long Cylinder: Calculates the shape coefficients of a long elliptical (or circular) beam (or pipe) with the fluid flowing at right-angles to the axis of the beam
Block Prism: Calculates the shape coefficients of a square block with the fluid flowing at right-angles to the flat end of the block
Block Cylinder: Calculates the shape coefficients of a circular block with the fluid flowing at right-angles to the flat end of the block
Elliptical Sphere: Calculates the shape coefficients of an elliptical sphere
Rectangular Plate: Calculates the shape coefficients of a rectangular plate with the fluid flowing at right-angles to the flat face
Circular Plate: Calculates the shape coefficients of a circular plate with the fluid flowing at right-angles to the flat face
All the above calculation options require the same input data and supply the same output data as follows:
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You enter: |
and the added mass and drag calculator will provide: |
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Coefficient of Drag
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Coefficient of Added Mass
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Coefficient of Inertia
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