Influence of After Body Shape on the Performance of Blunt Shaped Bodies as Vortex Shedders

Authors: Lavish Ordia, A. Venugopal, Amit Agrawal, S. V. Prabhu

Abstract:

The present study explores flow visualization experiments with various blunt shaped bluff bodies placed inside a circular pipe. The bodies mainly comprise of modifications of trapezoidal cylinder, most widely used in practical applications, such as vortex flowmeters. The present configuration possesses the feature of both internal and external flows with low aspect ratio. The vortex dynamics of bluff bodies in such configuration is seldom reported in the literature. Dye injection technique is employed to visualize the complex vortex formation mechanism behind the bluff bodies. The influence of orientation, slit and after body shape is studied in an attempt to obtain better understanding of the vortex formation mechanism. Various wake parameters like Strouhal number, vortex formation length and wake width are documented for these shapes. Vortex formation both with and without shear layer interaction is observed for most of the shapes.

Keywords: Flow visualization, Reynolds number, Strouhal number, vortex, vortex formation length, wake width.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1335730

References:

[1] Zdravkovich, M. M. (2003). Flow around circular cylinders: applications (Vol. 2). Oxford University Press
[2] Igarashi, T. (1999). Flow resistance and Strouhal number of a vortex shedder in a circular pipe. JSME International Journal. Series B, fluids and thermal engineering, 42(4), 586-595
[3] Gandhi, B. K., Singh, S. N., Seshadri, V., & Singh, J. (2004). Effect of bluff body shape on vortex flow meter performance. Indian Journal for Engineering and Material Sciences, 11, 378-384.
[4] Kamemoto, K., Yokoi, Y., Tanaka. E., 1992 “Observations on the Flow around Circular Cylinder and Trapezoidal Cylinder in a Circular Pipe by Dye - Injection Method.” 11th Australasian Fluid Mechanics Conferences University of Tasmania, Hobart, Australia., 14-18 December, pp. 699 - 702.
[5] Venugopal, A., Agrawal, A., Prabhu, S. V., “Frequency Detection in Vortex Flowmeter for Low Reynolds Number using Piezoelectric Sensor and Installation Effects.” Sensors and Actuators A., Vol. 184, pp. 78-85, 2012.
[6] Venugopal, A., Agrawal, A., Prabhu, S. V., "Influence of Blockage and Shape of a Bluff Body on the Performance of Vortex Flowmeter with Wall Pressure Measurement." Measurement, Vol. 44, 2011, pp. 954 – 964.
[7] Venugopal, A., Agrawal, A., & Prabhu, S. V. (2011). Review on vortex flowmeter—Designer perspective. Sensors and Actuators A: Physical, 170(1), 8-23.
[8] Takamoto, M., Terao, Y., (1999) “Standardization of Vortex Shedding Flowmeter.” Proceedings of the 4th International Symposium on Fluid Flow Measurement, July, Denver, USA.
[9] Venugopal, A., Agrawal, A., Prabhu, S. V., 2010 “Influence of Blockage and Upstream Disturbances on the Performance of a Vortex Flowmeter with a Trapezoidal Bluff Body.” Measurement, Vol. 43, pp. 603 - 616.