Faculty Publications
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Item Development of a chassis mounted multi stage axial flow turbine for wind energy harvesting on a cruising transport vehicle - A CFD based approach(American Society of Mechanical Engineers, 2016) Hegde, S.S.; Thamban, A.; Ahmed, A.; Upadhyay, M.; Mahalingam, A.Fossil fuels have been a means of energy source since a long time, and have tended to the needs of the large global population. These conventional sources are bound to deplete in the near future and hence there is a need for producing energy from renewable energy sources like solar, wind, geothermal, tidal etc. Technologies involving renewable energy are a growing subject of concern. Further, the problem is also one of excessive pollution caused by conventional sources of energy and their impact on the environment. In particular, one of the main sources of pollution is harmful gases emitting out of automobiles. Wind energy is one among the renewable energy sources which is implemented in large scale energy production to supplement growing domestic energy needs. Significant amount of research has been done in this field to harness energy to power household and other amenities using wind farms. The aim of this project is to come up with a low cost solution for wind energy harvesting on moving vehicles. The purpose of this study is to consider the use of wind energy along with conventional energy sources to power automobiles. This would help reduce the use of fossil fuels in automobiles and hence reduce the resulting environmental pollution. Also since the turbine adds to the weight of the vehicle the aim also is to minimize the weight of the turbine. Extensive structural analysis is done for this purpose to choose a material which would be both light weight and also be able to withstand the stresses developed. In the current paper the drag force produced in automobiles is harvested by using a convergent divergent nozzle mounted below the chassis of the car. Initially drag analysis is done in order to determine the increase in drag force produced after mounting of the nozzle. It is found from existing literature that the drag increases by 3.4% after the mounting of the nozzle making it possible the mounting of a nozzle beneath the car. Additionally exhaust gases is also allowed to pass through the same duct to increase the mass flow to the turbine and thus generate more energy. This is made to strike the blades of a 2 stage axial flow turbine whose rotation generates energy. The power output from the turbine is the parameter of interest. This energy can also be stored in batteries and be used to run auxiliary equipment of the automobile including the air conditioner. The exhaust gases will be passed through a catalytic converter before striking the blades of the turbine in order to prevent corrosion of the blades. Computational Fluid Dynamics (CFD) is used to validate the concept and also come up with a design that maximizes energy generation by such turbines. Numerical results obtained by simulation are validated by theoretical calculation based on turbines inlet and outlet velocity triangles. The future scope of the project would include the use of multiple nozzles in order to study its performance. © Copyright 2016 by ASME.Item Highway mounted horizontal axial flow turbines for wind energy harvesting from cruising vehicles(American Society of Mechanical Engineers (ASME) infocentral@asme.org, 2016) Hegde, S.S.; Thamban, A.; Bhai, S.P.M.; Ahmed, A.; Upadhyay, M.; Joishy, A.; Mahalingam, A.Renewable energy technologies are a growing subject of concern these days. Wind energy is one among the renewable energy sources which has been implemented in a large scale for energy production. A large amount of capital has been invested in this field to harness energy and power homes. Wind energy from highways is usually unused and can provide a considerable amount of wind energy to drive a turbine due to high vehicle traffic and the speed of the vehicles. Extensive research on wind patterns is required to determine the average velocity of the wind created by oncoming vehicles. The objective of this work is to design and analyze a horizontal axis wind turbine to capture wind energy from moving vehicles on the highway. A computational fluid dynamics approach is used to solve this problem. The major innovation in this paper is that wind energy is being harvested in a very unique manner and also turbine power calculations have been done to quantify the amount of energy being harvested. Although a few of the literatures have discussed similar ideas power quantification has never been done. Also the entire mechanism has been simulated in MATLAB to find out the number of cars required to charge a battery which is very unique to this paper. Power calculations have been done for the turbine and validated against theoretical calculations which were done using the concept of velocity triangles. The idea is to have a separate mounting for cars and heavy vehicles which can be realized by having separate lanes on highways. The analysis will be done for vehicles moving in a range of speeds on the highway. The wind turbines will be placed on overhead shafts (the height of which is be determined suitably) thereby capturing the wind generated as a result of pressure difference. The mounts can also be used as signboards for vehicles moving on the highway and hence serve a dual purpose. In addition, extensive structural and fatigue analysis will be done for the turbines and the mounting structures in order to determine a suitable material for the turbine as well as the mounts to withstand the forces generated. Using all of the collected energy, existing amenities such as street lights on the medians can be powered by these wind turbines. Thus the main objective of this work is to complement the conventional electrical energy used for powering amenities along highways by a renewable source of energy (wind power) thereby leading to the concept of sustainable highways. © © 2016 by ASME.Item Energy Harvesting from Vortex Induced Vibrations Using Vented Cylinders Mounted on Light Rail Locomotive(IEEE Computer Society help@computer.org, 2016) Kumar, K.R.; Morab, S.; Shekar, S.; Mahalingam, A.Majority of the population is dependent on the fossil fuels which are the conventional sources of the energy. Since fossil fuels are non-renewable they are bound to deplete in the near future. Leading edge research on the renewable sources of energy like wind energy, solar energy etc. Is a growing concern which has to replace the conventional energy sources to prevent environmental pollution and global warming. Wind energy is one among the renewable energy which is used for large scale power production using turbines, wind mills and power houses. Harvesting energy from vibrations caused because of alternative vortex shedding due to fluidic flow over a bluff body is under progressive research. The purpose of this study is to harvest wind energy from cross flow vibrations using vented cylinders mounted on the chassis of the train. In this study usage of vented cylinders over a normal baseline cylinder is of major concern to enhance vortex shedding and to extract maximum amount of energy considering a typical single carriage of a train. Using Computational fluid dynamics, Strouhal number is calculated which is validated and further designing a system for harvesting energy from vibrations. © 2016 IEEE.Item Numerical Analysis of Wall Shear Stress Parameters of Newtonian Pulsatile Blood Flow Through Coronary Artery and Correlation to Atherosclerosis(Springer Science and Business Media Deutschland GmbH, 2020) Buradi, A.; Mahalingam, A.The formation of atherosclerosis mainly depends on local hemodynamic blood flow parameters. The spatial and temporal variation of hemodynamic blood flow parameter is considered as an important factor for atherogenesis. The laminar, Newtonian pulsatile blood flow is considered for hemodynamic analysis of the idealized non-stenosis human coronary artery. To model and study the relationship between relative residence time (RRT), time-averaged wall shear stress (WSS) vector (TAWSSV), oscillatory shear index (OSI), and time-averaged WSS (TAWSS) the computational fluid dynamics technique are used. The study shows that higher OSI values are predicted at lower TAWSS and TAWSSV. At the low TAWSS areas the RRT attains a higher value, the region with high RRT correlates with atherosclerotic lesions on the artery wall. The local differences between RRT, OSI, and WSS magnitude may help to find predominantly where the atherosclerotic lesion progresses and develops at specific locations of the artery. © 2020, Springer Nature Singapore Pte Ltd.Item Comparative study on the effect of single coil and multi coil magnetorheological damper through finite element analysis(IOP Publishing Ltd, 2020) Kariganaur, A.K.; Kumar, H.; Mahalingam, A.Magnetorheological damper is vibration reducing system in which the magnetorheological fluid is the operating liquid which changes its behaviour with external stimulus by increasing the yield stress of fluid with the application of external magnetic field. Most of the vibration reducing equipment's is operated with single coil, and in this paper, study of multi coil magnetorheological damper is discussed and compared with the single coil for its magnetic flux density of the applied currents is studied by dividing equal and unequal number of turns of the coil in multi coil unlike in single coil damper. © Published under licence by IOP Publishing Ltd.Item Numerical analysis of the effect of turbulence transition on the hemodynamic parameters in human coronary arteries(AME Publishing Company info@amepc.org, 2016) Mahalingam, A.; Gawandalkar, U.U.; Kini, G.; Buradi, A.; Araki, T.; Ikeda, N.; Nicolaïdes, A.; Laird, J.R.; Saba, L.; Suri, J.S.Background: Local hemodynamics plays an important role in atherogenesis and the progression of coronary atherosclerosis disease (CAD). The primary biological effect due to blood turbulence is the change in wall shear stress (WSS) on the endothelial cell membrane, while the local oscillatory nature of the blood flow affects the physiological changes in the coronary artery. In coronary arteries, the blood flow Reynolds number ranges from few tens to several hundreds and hence it is generally assumed to be laminar while calculating the WSS calculations. However, the pulsatile blood flow through coronary arteries under stenotic condition could result in transition from laminar to turbulent flow condition. Methods: In the present work, the onset of turbulent transition during pulsatile flow through coronary arteries for varying degree of stenosis (i.e., 0%, 30%, 50% and 70%) is quantitatively analyzed by calculating the turbulent parameters distal to the stenosis. Also, the effect of turbulence transition on hemodynamic parameters such as WSS and oscillatory shear index (OSI) for varying degree of stenosis is quantified. The validated transitional shear stress transport (SST) k-? model used in the present investigation is the best suited Reynolds averaged Navier-Stokes turbulence model to capture the turbulent transition. The arterial wall is assumed to be rigid and the dynamic curvature effect due to myocardial contraction on the blood flow has been neglected. Results: Our observations shows that for stenosis 50% and above, the WSSavg, WSSmax and OSI calculated using turbulence model deviates from laminar by more than 10% and the flow disturbances seems to significantly increase only after 70% stenosis. Our model shows reliability and completely validated. Conclusions: Blood flow through stenosed coronary arteries seems to be turbulent in nature for area stenosis above 70% and the transition to turbulent flow begins from 50% stenosis. © Cardiovascular Diagnosis and Therapy. All rights reserved.Item Developing a clients’ charter and construction project KPIs to direct and drive industry improvements(Emerald Group Publishing Ltd. Howard House Wagon Lane, Bingley BD16 1WA, 2017) Kumaraswamy, M.; Mahesh, G.; Mahalingam, A.; Loganathan, S.; Kalidindi, S.N.Purpose: The purpose of this paper is to present a case, with live examples from a construction industry development initiative in India, for developing a proactive construction clients charter; and a core set of key performance indicators (KPIs), as basic tools for facilitating the expectations of this special issue in “securing clients’ organisational objectives and project aspirations throughout construction project lifecycles” apart from empowering construction industry improvements in general. Design/methodology/approach: Having identified 19 critical issues in the Indian construction industry at two construction clients-academia roundtables, two of the “action teams” formed to address specific issue sets, separately developed a relevant construction clients charter and useful KPIs, respectively, through a combination of literature reviews and brainstorming conference calls, along with iterative drafts of, and feedback on interim outputs. Validation of “working papers” presented at a “Consolidation Roundtable” of construction clients and their consultants, elicited further suggestions for fine tuning of final outputs. Findings: The charter was formulated in structured steps, including identifying “priorities” under four categories: overall, expectations from supply chains, by supply chains and by end users. The six sub-heads of the charter are on procurement, design, innovation and technology, project execution, human resource development and worker welfare, and quality, safety and sustainability. The “suggested KPIs” for building clients in India enable organisations to choose: from three different groups (i.e. design phase, construction phase, or business outcomes), and at three different levels (i.e. project/organisation level, benchmarking club level, or industry level). Originality/value: There is no known overarching Construction Clients’ Charter at present. Some project KPI sets are available elsewhere. However, those developed in India, while focusing on project performance, also connect to organisational performance and business outcomes. Furthermore, KPIs are provided to separately probe client, consultant and contractor performance. Significantly, the charter and KPIs are outcomes from an industry-led self-improvement initiative launched with building construction clients at the forefront, rather than a top-down imposition from government. Furthermore, while prioritising client aspirations, they also address common supply chain and end-user concerns, which may also be interpreted as a longer-term win-win-win client’s aspiration. © 2017, © Emerald Publishing Limited.Item Evaluation of optimal parameters of MR fluids for damper application using particle swarm and response surface optimisation(Springer Verlag service@springer.de, 2017) Gurubasavaraju, T.M.; Kumar, H.; Mahalingam, A.The controllable rheological properties of MR fluid exhibit viscoelastic properties within pre-yield, which are essential for the characterization of MR dampers for the isolation of vibration. In the present work, using particle swarm optimisation (PSO), it is identified that the proportion of MR fluid constituents, fluid gap and current are the parameters which influence majorly on the rheological properties and damping effect of MR damper. Initially, rheological properties of the prepared MR fluid samples are determined using rotational plate–plate type rheometer with the magnetorheological device cell attachment by keeping three levels of gap between the parallel plates. Three different proportions of MR fluid are prepared based on the volume fraction of carbonyl iron particle, i.e., 25, 30 and 35% in the silicone carrier fluid along with 1% of lithium-based grease as stabiliser. The objective function of this optimisation problem is to maximise the shear stress and damping force of the MR damper. The design of experiment (DOE) is employed to obtain the various combinations of parameters and their respective responses. The interaction of the regression model obtained from the DOE is used in PSO to evaluate the optimal parameters. The results indicated that the MR fluid with the particle concentration of 31% is the optimal proportion for MR damper application. © 2017, The Brazilian Society of Mechanical Sciences and Engineering.Item Effect of stenosis severity on wall shear stress based hemodynamic descriptors using multiphase mixture theory(Isfahan University of Technology secretary@jafmonline.net, 2018) Buradi, A.; Mahalingam, A.A variety of wall shear stress (WSS) based hemodynamic descriptors have been defined over the years to study hemodynamic flow instabilities as potential indicators or prognosticators of endothelial wall dysfunction. Generally, these hemodynamic indicators have been calculated numerically using 'single phase' approach. In single phase models, the flow-dependent cell interactions and their transport are usually neglected by treating blood as a single phase non- Newtonian fluid. In the present investigation, a multiphase mixture-theory model is used to define the motion of red blood cells (RBCs) in blood plasma and interactions between these two-components. The multiphase mixture theory model exhibited good agreement with the experimental results and performed better than non-Newtonian single phase model. The mixture-theory model is then applied to simulate pulsatile blood flow through four idealized coronary artery models having different degrees of stenosis (DOS) severities viz., 30, 50, 70 and 85% diameter reduction stenosis. The maximum WSS is seen at the stenosis throat in all the cases and maximum oscillatory shear index (OSI) is seen in downstream region of the stenosis. Our findings suggest that for degree of coronary stenosis more than 50%, a more disturbed fluid dynamics is observed downstream of stenosis. This could lead to further progression of stenosis and may promote a higher risk of atherogenesis and plaque buildup in the flow-disturbed area. The potential atherosclerotic lesion sites were identified based on clinically relevant values of WSS, timeaveraged WSS gradient (TAWSSG), time-averaged WSS (TAWSS), and OSI. Finally, the change in potential atherosclerotic lesion sites with respect to DOS has been quantified. © 2018, Isfahan University of Technology.Item An approach for characterizing twin-tube shear-mode magnetorheological damper through coupled FE and CFD analysis(Springer Verlag service@springer.de, 2018) Gurubasavaraju, T.M.; Kumar, H.; Mahalingam, A.The most promising technology in the field of semi-active suspension systems is the use of magnetorheological property of MR fluid, whose material behavior can be controlled through external magnetic field. Devices developed based on this principle are adaptive and controllable as desired for a specific application. It is important to understand the damping characteristics of these devices before employing them, using experimental or computational approaches. In the present work, both experimental and computational methods have been adopted for characterizing a twin-tube MR damper with an intention to develop a computational approach as an alternative to experimental test in the preliminary design stage. Initially, experimental characterization of MR damper was carried out at 1.5 and 2 Hz frequencies for damper stroke length of ± 5 mm under different DC currents ranging from 0.1 to 0.4 A. Later, coupled finite-element and computational fluid dynamic analysis has been carried out to estimate the damping force under same conditions as used in the experiment. The results of computation are in good agreement with experimental ones. Furthermore, using this computational approach, the damping force at different frequencies of 1.5, 2, 3, and 4 Hz has been estimated and its time histories are also plotted. The influence of fluid flow gap on the damping force has been determined and results revealed that damping force behaves inversely with fluid flow gap. © 2018, The Brazilian Society of Mechanical Sciences and Engineering.