COBEM99

SR18 Métodos Experimentais em Termofluidodinâmica

Title:

STROUHAL NUMBER DETERMINATION FOR SEVERAL REGULAR POLYGON CYLINDERS FOR REYNOLDS NUMBER UP TO 600

Summary :

ABSTRACT. EXPERIMENTAL FLOW VISUALIZATION IS A POWERFUL TOOL TO UNDERSTANDING THE COMPLEX PHENOMENA ASSOCIATED WITH THE FLUID DYNAMICS. THIS WORK LINKS THAT IMPORTANT EXPERIMENTAL TECHNIQUE WITH THE IMAGE PROCESSING, OBJECTING AN INVESTIGATION OF THE VORTEX SHEDDING FROM SEVERAL PRISMATIC BLUFF BODY CYLINDERS WITH CROSS SECTION FORMED BY REGULAR POLYGONS - TRIANGULAR, PENTAGONAL, HEXAGONAL AND OCTAGONAL. EXPERIMENTS WERE PERFORMED IN A PILOT VERTICAL LOW TURBULENCE HYDRODYNAMIC TUNNEL, WITH 146X146X500 MM OF TEST SECTION. THE EMISSION OF LIQUID DYE DIRECTLY IN NON-PERTURBED FLOW BY MEANS OF A LONG HYPODERMIC NEEDLE HAS BEEN UTILIZED TO CREATE THE FLOW IMAGE. A 3 CCD HIGH-RESOLUTION VIDEO CAMERA HAS BEEN USED TO IMAGE CAPTURE AND STROUHAL NUMBER IS DETERMINATE BY IMAGE PROCESSING FOR REYNOLDS NUMBERS UP TO 600. THE KNOWLEDGE OF THE STROUHAL NUMBER BEHAVIOR IN FUNCTION OF REYNOLDS NUMBER FOR SEVERAL RIGID BODY SHAPES IS MUCH IMPORTANT AS AID TO VORTEX METER PROJECTS. KEYWORDS: VORTEX METER, STROUHAL NUMBER, FLOW VISUALIZATION, VORTEX SHEDDING.

Author :

Gonçalves, Herbert Carlos
Vieira, Edson Del Rio

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