Qualification: 
Ph.D
v_sivadas@cb.amrita.edu

Dr. Sivadas V. comes to Amrita with national and international experience and reputation. He received his Ph. D. from IIT Bombay, specializing in Transverse Turbulent Jets utilizing optical diagnostic techniques. He was a Council of Scientific and Industrial Research (CSIR) Fellow while at IIT. 

In 1991, he worked as a German Academic Exchange Service (DAAD) Fellow at the German Aerospace Research Establishment (DLR)-Gottingen. This was followed by a Portuguese Science and Technology Fellowship in 2000 in the area of sprays and liquid film disintegration at the Insituto Superior Technico (IST) in Lisbon, Portugal under the European Commission DIME (Dynamics of Institution and Markets in Europe) program. The project focused on direct injection spray engine processes and mechanisms to improve performance. As part of this project, he participated in a short-course on the latest advances in Spray Technology at Carnegie Mellon University, USA under Professor Norman Chigier. 

Before joining Amrita, Dr. Vayalakkara worked at Nanyang Technological University in Singapore teaching courses in Mathematics and Fluid Mechanics and doing research in Surface Wave Dynamics under the Singapore-Stanford Partnership (SSP) with Stanford University, USA. 

He is a member of the American Association for the Advancement of Science and has been featured in Who's Who in the World and Who's Who in Finance and Industry.

Publications

Publication Type: Journal Article

Year of Publication Publication Type Title

2018

Journal Article

Balaji K., Dr. Sivadas V., Radhakrishna, V., A.B., K., and Saicharan, K., “Experimental Characterization of Intrinsic Properties Associated with Air-Assisted Liquid Jet and Liquid Sheet ”, Journal of Fluids Engineering, Transactions of the American Society of Mechanical Engineers (ASME), vol. 140, no. 5, pp. 051301/1-9 , 2018.[Abstract]


The present study focuses on experimental characterization of interfacial instability pertinent to liquid jet and liquid sheet in the first wind-induced zone. To accomplish this objective, the interfacial wave growth rate, critical wave number, and breakup frequency associated with air-assisted atomizer systems were extracted by utilizing high-speed flow visualization techniques. For a range of liquid to gas velocities tested, nondimensionalization with appropriate variables generates the corresponding correlation functions. These functions enable to make an effective comparison between interfacial wave developments for liquid jet and sheet configurations. It exhibits liquid sheets superiority over liquid jets in the breakup processes leading to efficient atomization.

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2016

Journal Article

Dr. Sivadas V., Balaji K., Sampathkumar, Mc, Hassan, M. Md, Karthik, K. Me, and Saidileep, Kb, “Empirical Correlation of the Primary Stability Variable of Liquid Jet and Liquid Sheet under Acoustic Field”, Journal of Fluids Engineering, Transactions of the ASME, vol. 138, 2016.[Abstract]


The investigation focuses on optimizing the length of wind-pipe that transmits acoustic energy from the compression driver to the cavity of twin-fluid atomizers. To accomplish this objective, the primary variable of stability, that is, the breakup length of liquid jet and sheet under acoustic perturbations has been experimentally characterized for a range of wind-pipe length and liquid velocity. The analysis considers liquid phase Weber number in the range of 0.7-8, and the results are compared with primary breakup data without acoustic perturbations. The range of Weber number tested belongs to Rayleigh breakup zone, so that inertia force is negligible compared to surface tension force. It shows the existence of unique stability functions based on dimensionless products up to an optimum wind-pipe length, which extends greater for liquid sheet configuration. The present results may find relevance in atomizer design that utilizes acoustic source to enhance liquid column breakup processes. More »»

2013

Journal Article

Dr. Sivadas V., Aravind, R., Vignesh, E., Krishnaraj, I., and Balaji, K., “Area Void Fraction Associated with Twin-Fluid Atomizer”, Atomization and Sprays , Begell House, vol. 23, no. 8, pp. 663-676, 2013.[Abstract]


An empirical characterization of the void fraction in the spray region of liquid jets emanating from a twin-fluid atomizer has been carried out. The present study evolves under primary breakup criteria. That is, the respective breakup length extracted from flow visualization techniques are successfully utilized to find a better functional correlation for the area void fraction with longitudinal distance. The resultant function enables extracting the axial location at which complete atomization occurs for the range of conditions tested. To make the analysis more appealing in the practical domain, the concept of effective jet diameter and associated stretching factor at the nozzle exit plane were introduced. Hence, the validity of results will not be limited to the present test conditions.

 

 

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Faculty Research Interest: 
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