Free and Forced Vortex Apparatus (MODEL ME-FM-1293E-R)

The ARL’s 1293E Free & Forced Vortex Apparatus is designed to produce and measure the characteristics of free and forced vortices.

  • Cylindrical vessel with four inlet/outlet ports to generate free and forced vortices
  • Three interchangeable orifices and paddle wheel to fit in base of tank
  • Measuring bridge with adjustable pointers and internal caliper to measure vortex dimensions
  • Pitot tubes for estimation of velocities in vortex
  • Quick-release fittings for easy connection to hydraulics bench

The 1293E apparatus comprises a clear acrylic cylinder on a plinth designed to produce and measure free and forced vortices. The free vortex is generated by water discharging through an interchangeable orifice in the base of the cylinder, and the resulting profile is measured using a combined caliper and depth scale. The forced vortex is induced by a paddle in the base of the cylinder, which is rotated by jets of water. The profile of the forced vortex is determined using a series of depth gauges.

Velocity at any point in the free or forced vortices may be measured using the appropriate pitot tube supplied. Dye crystals (not supplied) may be used to demonstrate secondary flow at the base of the free vortex.

Tank diameter:245mm
Height to overflow point:180mm
Orifice diameters:8, 16 and 24mm
Forced vortex measuring probes
Distance from centre:
0, 30, 50, 70, 90 and 110mm
Pitot tubes having measuring
point (nose) at:
15, 25 and 30mm radius
Inlet tubes:9 and 12.5mm diameter
  • Understanding the difference between free and forced vortices
  • Determining the surface profile of a forced vortex
  • Determining the surface profile and total head distribution of a free vortex
  • Visualization of secondary flow in a free vortex

Hydraulics Bench

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