Journal article


Investigation of drag reduction due to dimpled surfaces in narrow channels by means of flow simulations


Publication Details
Author(s): Praß J, Franke J, Becker S
Publication year: 2017
Volume: 871
Conference Proceedings Title: Proceedings in Applied Mathematics and Mechanics
Pages range: 244--251
ISSN: 1660-9336
Language: English

Abstract

Reduction of drag and flow resistance in systems containing moving fluids is a prominent tool to increase energy efficiency. Besides active flow control – such as moving surfaces or boundary layer suction – passive techniques such as surface patterning by means of dimples are promising since no additional energy consumer is introduced into the system. Even though the effect of drag reduction due to dimples has often been observed, the physical principals responsible for this effect are not yet understood. Most of the research concerning dimples and drag reduction published so far has been carried out experimentally, not many numerical investigations on this topic have been done. The main reason for this is that the tiny, transient flow structures generated in direct vicinity of dimples can not easily be resolved in simulations. Even in case of time dependent numerical investigations it is not clear, whether and with which method of sub-grid scale modeling Large Eddy Simulations are capable of modeling these structures sufficiently. In this work we investigated different surfaces with dimple depth to diameter ratios h/D reaching from 0.01 to 0.1 in channels of height H = 0.417D at Reynolds numbers ReD 5 830 and ReD 11 650 using steady state simulations with a k-omega-SST turbulence model. Drag reductions were observed for all setups h/D < 0:08 compared to the smooth channel. The best results were obtained with dimple depths of 4-5 % of diameter showing a slight dependence of Re which is in good agreement with literature. As the experimental investigation of the flow over dimpled surfaces is limited in spacial and temporal resolution we could demonstrate that numerical investigations give the possibility to overcome this drawback. However the solution of simulations strongly depends on numerous factors such as the discretization scheme, the numerical models and the grid used to obtain results which might be a reason for slightly varying results of such simulations found in literature.



How to cite
APA: Praß, J., Franke, J., & Becker, S. (2017). Investigation of drag reduction due to dimpled surfaces in narrow channels by means of flow simulations. Applied Mechanics and Materials, 871, 244--251. https://dx.doi.org/10.4028/www.scientific.net/AMM.871.244

MLA: Praß, Julian, Jörg Franke, and Stefan Becker. "Investigation of drag reduction due to dimpled surfaces in narrow channels by means of flow simulations." Applied Mechanics and Materials 871 (2017): 244--251.

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