KARMAN'S VORTEX STREET FLOWMETER

PURPOSE:To detect vortexes in a broad range of flow speeds with a good SN ratio, by arranging vortex yielding pillar shaped bodies, namely, an upstream pillar shaped body whose cross section is an isosceles triangle shape and a downstream pillar shaped body whose cross section is an isosceles trapezoid, both having the equal projection length in the flowing direction, in a pentagon form, with a specified interval being provided. CONSTITUTION:The bottom side part of an upstream pillar shaped body 2, whose cross section is approximately an isosceles triangle shape and the bottom side part of a downstream pillar shaped body 3, whose cross section is approximately an isosceles trapezoid shape, are arranged in parallel in the flowing direction of fluid with a specified interval l being provided. They are vertically inserted into the flow. Projected lengths of the upstream pillar shaped body 2 and the downstream pillar shaped body 3 in the flowing direction, which are perpendicular to the flowing direction, i.e. representative lengths d1 and d2, are made approximately equal. According to the result of the experiment, the stablest vortexes are yielded when the representative lengths of the upstream and downstream pillar shaped bodies are approximately equal (d1=d2=d), and the vortexes can be detected with a good SN ratio.