When the effective angle of the diffuser was increased with an increase of the bluff body
(nose-down) pitch, the vortices moved forward and strengthened due to the induced inflow, preventing the formation of a separation bubble on the diffuser ramp.
et al., "Experimental and Computational Study of Unsteady Wake Flow Behind a Bluff Body
with a Drag Reduction Device," SAE Technical Paper 2001-01-1042, 2001, doi:10.4271/2001-01-1042.
Bilger, "Turbulent diffusion flames of hydrocarbon fuels stabilized on a bluff body
," Symposium (International) on Combustion, vol.
The obstruction (bluff body
) placed in the flow of the liquid sheds vortices downstream at a frequency proportional to the velocity of the liquid.
The unit consisted of a fixed flat plate as a bluff body
with a piezoelectric membrane placed in the wake.
Ride isn't matched by refinement, though -- road rumble is ever-present, and of course that bluff body
sets up no end of wind noise.
While the measurement principle of the SwirlMaster is based on concentric swirls that create pressure fluctuations in the medium, the VortexMaster works according to the Karman vortex principle with turbulences generated by a bluff body
. Both series have a piezo sensor with multiple elements to register the measured signals and additionally the pipe vibrations with which the measurement signal is compensated.
The sensor is based upon the vortex flow measurement principle, which uses a bluff body
in the flow path to create small eddy currents (vortices) and the pressure of this current is measured to determine the flow through a given cross sectional area.
The devices use a bluff body
obstruction to produce vortices, and an electronic transducer measures these oscillations to provide a signal proportional to flow rate.
In the case of the golf ball, which is a so-called bluff body
in aerodynamic parlance, the form or pressure drag component dominates.
The problem encountered is somewhat different from the classical bluff body
flow in which the bluff body
At the latter half of the 19th century and the beginning of the 20th, researchers such as John Strutt (Lord Rayleigh) and Theodore von Karmain discovered that strings in a wind move perpendicular to the flow of air, and that vortices trail behind a bluff body
in a regular pattern.