NDLI: Vortex dynamics and mass entrainment in turbulent lobed jets with and without lobe deflection angles

Content Provider	Springer Nature Link
Author	Nastase, Ilinca Meslem, Amina
Copyright Year	2009
Abstract	Passive control of jet flows in order to enhance mixing and entrainment is of wide applicative interest. Our purpose is to develop new air diffusers for HVAC systems, by using lobed geometry nozzles, in order to ameliorate users the thermal comfort. Two turbulent 6-lobed air jets with and without lobe deflection angles were studied experimentally and compared with a reference circular jet having the same initial Reynolds number. The main objective was to analyze the modifications occurring in the vortex dynamics of the flow, firstly by replacing a circular tube with a straight lobed tube, and secondly by a lobed tube having a double inclination of the lobes. Rapid visualizations of the flows and hot-wire measurements of the streamwise velocity spectra allow understanding the vortex roll-up mechanisms. Unlike the circular jet, where the primary rings are continuous, the Kelvin–Helmholtz vortices in the lobed jet flows were found to be discontinuous. The resulting “ring segments” detach at different frequencies whether they are shed in the lobe troughs or at the lobe sides. One explanation relies on the strong variation of the exit plane curvature. Additionally, a speculative scenario of the vortical dynamics is advanced by the authors. The discontinuous nature of the K–H vortices enables the development of secondary streamwise structures, non-influenced by the passage of the primary structures as in the case of the circular jet. Thus, the momentum flux transport role played by the streamwise structures is rendered more efficient and leads to a spectacular increase in the entrainment rate in the initial region. The amount of fluid being entrained in the lobed jet by the streamwise structures is drastically amplified by the double inclination of the nozzle exit boundary.
Starting Page	693
Ending Page	714
Page Count	22
File Format	PDF
ISSN	07234864
Journal	Experiments in Fluids
Volume Number	48
Issue Number	4
e-ISSN	14321114
Language	English
Publisher	Springer-Verlag
Publisher Date	2009-10-25
Publisher Place	Berlin, Heidelberg
Access Restriction	One Nation One Subscription (ONOS)
Subject Keyword	Engineering Thermodynamics, Heat and Mass Transfer Fluid- and Aerodynamics Engineering Fluid Dynamics
Content Type	Text
Resource Type	Article
Subject	Fluid Flow and Transfer Processes Physics and Astronomy Mechanics of Materials Computational Mechanics

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in

Mixing and entrainment in the near field of turbulent round jets

Correlative analysis of organised structures in turbulent jets

Measurements of air entrainment by vertical plunging liquid jets

Conditional entrainment statistics of inertial particles across shearless turbulent interfaces

Mesler entrainment in alcohols

Plasma control of vortex flow on a delta wing at high angles of attack

Some observations in the vortex-turning behaviour of noncircular inclined jets

Turbulent spots in hypervelocity flow

PIV measurements of isothermal plane turbulent impinging jets at moderate Reynolds numbers

Vortex dynamics and mass entrainment in turbulent lobed jets with and without lobe deflection angles

Similar Documents

Mixing and entrainment in the near field of turbulent round jets

Correlative analysis of organised structures in turbulent jets

Measurements of air entrainment by vertical plunging liquid jets

Conditional entrainment statistics of inertial particles across shearless turbulent interfaces

Mesler entrainment in alcohols

Plasma control of vortex flow on a delta wing at high angles of attack

Some observations in the vortex-turning behaviour of noncircular inclined jets

Turbulent spots in hypervelocity flow

PIV measurements of isothermal plane turbulent impinging jets at moderate Reynolds numbers

Vortex dynamics and mass entrainment in turbulent lobed jets with and without lobe deflection angles