The objective of this paper is to investigate the effects of nozzle spacing on the mean velocity and higher-order turbulent statistics of free twin round jets produced from sharp contraction nozzles. The experiments were performed in an air chamber where four nozzle spacing ratios, S/d = 2.8, 4.1, 5.5, and 7.1, were investigated at a fixed Reynolds number of 10,000. A planar particle image velocimetry (PIV) system was used to conduct the velocity measurements. The results show that downstream of the potential core, a reduction in spacing ratio leads to an earlier and more intense interaction between the jets, indicated by enhanced half-velocity width spread rate in the inner shear layers and a significant rise of turbulent intensities and vorticity thickness along the symmetry plane. A reduction in spacing ratio, however, confines the ambient fluid entrainment along the inner shear layers leading to a reduced core jet velocity decay rate. The closer proximity of the jets also leads to the decrease of Reynolds stresses in the inner shear layers but not in the outer shear layers. The Reynolds stress ratios along the jet centerline reveal the highest anisotropy in the potential core region.
Experimental Investigation of Nozzle Spacing Effects on Characteristics of Round Twin Free Jets
Contributed by the Fluids Engineering Division of ASME for publication in the JOURNAL OF FLUIDS ENGINEERING. Manuscript received April 13, 2018; final manuscript received November 11, 2018; published online January 7, 2019. Assoc. Editor: Philipp Epple.
- Views Icon Views
- Share Icon Share
- Cite Icon Cite
- Search Site
Laban, A., Aleyasin, S. S., Tachie, M. F., and Koupriyanov, M. (January 7, 2019). "Experimental Investigation of Nozzle Spacing Effects on Characteristics of Round Twin Free Jets." ASME. J. Fluids Eng. July 2019; 141(7): 071201. https://doi.org/10.1115/1.4041989
Download citation file:
- Ris (Zotero)
- Reference Manager