Turbulence generation by different types of impellers

Experimental analysis of hydrodynamics in a radially agitated tank

“…abrese, 1995;Schaffer et al, 2000;Sharp and Adrian, 2001 . Moreover, this technique enables the organized motion velocity to be extracted for a given blade position relative to the measurement plane: the trailing vortices can then be visualized.…”

Study of fluid flow in baffled vessels stirred by a Rushton standard impeller

“…For a Rushton impeller Schafer et al [25] suggested a threshold value of the non-dimensional parameter ξ c = 13 to identify the trailing vortex.…”

“…Derksen et al [10] and Schafer et al [25] characterized the vortex size considering a non-dimensional vorticity defined as…”

A simplified procedure to identify trailing vortices generated by a Rushton turbine

“…Whatever the experimental techniques [Laser‐Doppler velocimetry, particle image velocimetry (PIV)], data acquisitions are first synchronized with the blade position to measure phase‐averaged velocity components 34, 6–14 Before the work of EBL,5 two approaches were commonly used to localize the trailing vortices : (1) from the phase‐averaged velocity fields, for a given angular position of the measurement plane compared to the blade, the vortex center is defined by the location where the vertical velocity is nil, assuming that there is no vertical displacement of the vortices; (2) from a dimensionless vorticity (ξ), calculated in a vertical plane of measurement relative to the blade position, an identifier's threshold ξ c is arbitrarily fixed to identify the vortex region 11, 12…”