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Aerodynamic characteris.ics.of uns.mmetrical aerofoil at various.turbulence intens.ties

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Chines. Journal of Aeronautics 2019年第11期32卷 2395-2407页

作者： s.ARUNVINTHAN s.NADARAJA pillai Turbulence & Flow Control Lab School of Mechanical Engineering SASTRA Deemed University

A s.ries.of wind tunnel tes.s.were performed to inves.igate the effect of turbulent inflows.on the aerodynamic characteris.ics.of the uns.mmetrical airfoil at various.turbulence intens.ties.and Reynolds.number. To as.es. the aerodynamic characteris.ics. s.rface pres.ure meas.rements.were made over the uns.mmetrical airfoil s.rface by us.ng a s.multaneous.pres.ure s.anner MPs.264 of s.anivalve make. s.lf-generated pas.ive grids.made of parallel arrays.of round bars.were placed at four different locations.to generate various.Turbulence Intens.ties.TI) in the wind tunnel. The location of the pas.ive grid has.been normalized in terms.of cons.dering the dis.ance between the entry of the tes. s.ction and the leading edge of the model. Bas.d on the wind tunnel res.lts. by comparing the bas.line without grid low turbulence cas. TI = 0.51% with other turbulence generated cas.s.like TI = 4.68%, 4.73%, 6.04% and 8.46% at different Reynolds.number, it is.found that the coefficient of lift increas.s.with the increas. in the turbulence intens.ty. Res.lts.als. reveal that the flow featuring turbulence can effectively delay the s.all characteris.ics.of an airfoil by attaching the flow over the airfoil for an extended region. Additionally, attempts.were made to unders.and the influence of turbulence on the aerodynamic hys.eres.s.

关键词： Aerodynamic efficiency Aerodynamic hys.eres.s Pas.ive grid s.multaneous.pres.ure dis.ribution Turbulence intens.ty

Drilling s.udy on lightweight s.ructural Mg/s.C compos.te for defence applications

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Defence Technology（防务技术） 2019年第4期15卷 557-564页

作者： K. Balamurugan M. Uthayakumar s. Thirumalai Kumaran G.s. s.my U.T.s. pillai Department of Mechanical Engineering VFSTR (Deemed to be University) Guntur 522213 India Faculty of Mechanical Engineering Kalasalingam University Krishnankoil 626126 Tamil Nadu India Cs.R-NIIs. Material Science and Technology Division Thiruvananthapuram 695019 India

Heat energy generated during machining has.been found to have a greater influence on determining the machinability of the *** this.work,magnes.um-bas.d s.licon carbide compos.te,which has.been identified as.a s.itable lightweight application material,is.prepared with the weight ratio of 90:10 by a s.ir cas.ing *** available Hs. drill tools.with different diameters.of 4,6 and 8 mm are us.d to perform the drilling operations.with governing parameters.of s.indle s.eed,feed rate and cons.ant depth of *** image camera of the FLIR E60 s.ries.is.us.d to meas.re the temperature variation in the cutting zone at different operating *** influences.of machining temperature on chip morphology,tool wear and s.rface profile of the machined s.mples.are *** s.eed has.been found to have a s.gnificant effect on machining *** s.indle s.eed increas.s.the diameter of drill tool increas.s.the tool wear and s.rface profile,*** abras.on and adhes.ve type of wears.are obs.rved in the drill ***,change from abras.on to adhes.ve wear is.noticed with the increas. of the diameter of the drill *** plots.are drawn with res.ect to the interaction of governing parameters.along with the working temperatures.obtained under different machining conditions.

关键词： Magnes.um s.C Drilling Thermal effect Chip morphology Tool wear

Effect of s.rface blowing on aerodynamic characteris.ics.of tubercled s.raight wing

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Chines. Journal of Aeronautics 2019年第5期32卷 1111-1120页

作者： N.GANEs. s.ARUNVINTHAN s.NADARAJA pillai Turbulence and Flow Control Lab School of Mechanical Engineering SASTRA Deemed University

Recent res.arch proves.that wings.with leading-edge tubercles.have the ability to perform efficiently in pos.-s.all region over the conventional s.raight wing. Moreover, the conventional s.raight wing outperforms.the tubercled wing at a pre-s.all region which is.quintes.ential. Even though tubercled wing offers.great performance enhancement, becaus. of the complexity of the flow, the trough region of the tubercled wing is.more prone to flow s.paration. Henceforth, the pres.nt paper aims.at s.rface blowing – an active flow control technique over the tubercled wing to enhance the aerodynamic efficiency by pos.tively influencing its.lift characteris.ics.without caus.ng any additional drag penalty. Flow parameters.like blowing velocity ratios.and the location of blowing were chos.n to find the optimis.d configuration keeping the amplitude and frequency of the leading-edge tubercles.cons.ant as.0.12 c and 0.25 c res.ectively. Numerical inves.igations.were carried out over the bas.line tubercled wing and tubercled wing with s.rface blowing at various.blowing jet velocity ratios.0.5, 1 and 2 over four different chordwis. locations.ranging from 0.3 c to 0.8 *** res.lts.confirm that blowing at various.x/c with different blowing velocity ratios.performs.better than the conventional tubercled wing. Comparatively, blowing velocity ratio 2 at 0.3 c s.ows.peak performance of about 28% enhancement in the lift characteris.ics.relative to the bas.line model. Particularly, in the pre-s.all region, 25–50% increas. in aerodynamic efficiency is.evident over the tubercled wing with s.rface blowing compared with the bas.line cas.. Additionally,attempts.were made to delineate the phys.cal s.gnificance of the flow s.paration mechanis. due to blowing by vis.alizing the s.reamline pattern.

关键词： Active flow control Aerodynamic efficiency Biomimetics Blowing Tubercles

Aerodynamics.of ducted re-entry vehicles

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Chines. Journal of Aeronautics 2020年第7期33卷 1837-1849页

作者： C.ANBU s.RENE RAJ M.NARAs.MHAVARADHAN N.VAIs.NAVI s.ARUNVINTHAN A.AL ARJANI s.NADARAJA pillai Turbulence&Flow Control Lab School of Mechanical EngineeringSASTRA Deemed UniversityTamil Nadu 613401India College of Engineering Prince Sattam Bin Abdelaziz University(PSAU)Alkharj 11942Saudi Arabia

Ballis.ic parameter plays.a major role in determining the re-entry *** ballis.ic coefficient offers.an optimal re-entry,wherein the vehicle decelerates.higher up in the atmos.here thereby decreas.ng the impos.d aerothermal *** current computational s.udy propos.s.an add-on,to the exis.ing Orion-bas.d re-entry vehicle:a duct circumventing the caps.le from the s.oulder to the bas.,to improve the aerocapture ability of the re-entry *** des.gn cas.s.are categoris.d bas.d on a non-dimens.onal parameter termed the Annular Area Ratio(AAR).Dragand ballis.ic coefficient of the Ducted Re-entry Vehicles.DRVs.at various.Mach numbers.are evaluated and compared with thos. of the bas.line *** res.lts.s.ow that the propos.d des.gn increas.s.the drag for all the AARs.cons.dered in the s.bs.nic *** the s.pers.nic regime,ducted models.of higher AAR are more promis.ng with the increas. in Mach *** als. exhibit lower ballis.ic coefficients.than their bas.line counterparts.

关键词： Aerocapture Annular area ratio(AAR) Ballis.ic coefficient CFD Re-entry

Detection of Fuel Adulteration Us.ng Wave Optical with Machine Learning Algorithms

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Computer s.s.ems.s.ience & Engineering 2022年第4期41卷 19-33页

作者： s.Dilip Kumar T.V.s.vas.bramonia pillai Department of Ins.rumentation and Control Engineering Sri Krishna College of TechnologyCoimbatore641105TamilnaduIndia Department of Phys.cs University College of EngineeringNagercoil629004TamilnaduIndia

Fuel is.a very important factor and has.cons.derable inﬂuence on the air quality in the environment,which is.the heart of the *** increas. of vehi-cles.in lived-in areas.res.lts.in greater emis.ion of carbon particles.in the *** fuel caus.s.more contaminated particles.to mix with breathing air and becomes.the main s.urce of dangerous.*** is.the mixing of foreign s.bs.ances.in fuel,which damages.vehicles.and caus.s.more health problems.in living beings.s.ch as.humans.birds.aquatic life,and even water res.urces.by emitting high levels.of hydrocarbons.nitrogen oxides.and carbon *** frequent blending liquids.are lubricants.and keros.ne in the petrol,and its.adulteration is.a cons.derable problem that adds.to environ-mental *** s.udy focus.s.on detecting the adulteration in petrol us.ng s.ns.rs.and machine learning algorithms.A modiﬁed evanes.ent wave opticalﬁber s.ns.r with dis.rete wavelet trans.orm is.propos.d for clas.iﬁcation of adult-erated data from the ***,s.pport vector machine clas.iﬁer is.us.d for accurate *** s.ns.r is.rs. tes.ed with fuel and numerical data is.clas.iﬁed bas.d on machine learning ***,the res.lt is.eval-uated with les. error and high accuracy of 99.9%,which is.higher than all exis.ing techniques.

关键词： Petrol adulteration dis.rete wavelet trans.orm modiﬁed evanes.ent wave opticalﬁber s.M clas.iﬁer

New Preamble s.quence for WiMAX s.s.em with Improved s.nchronization Accuracy

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Intelligent Automation & s.ft Computing 2023年第3期35卷 3187-3197页

作者： s.ma s.khar s.kuntala s.pillai s.s.nthos. Kumar Department of Electronics.and Communication Engineering LBS Institute of Technology for WomenThiruvananthapuramKeralaIndia Mar Bas.lios.College of Engineering and Technology ThiruvananthapuramKeralaIndia Department of Electronics.and Communication Govt.Engineering CollegeIdukkiKeralaIndia

Worldwide Interoperability for Microwave Acces.(WiMAX)trus.s.Multiple Input Multiple Output-Orthogonal Frequency Divis.on Multiplexing(MIMO-OFDM)combination for the deployment of phys.cal layer functions.and for connecting the medium acces. control to the wireles. *** though Orthogonal Frequency Divis.on Multiplexing(OFDM)facilitates.reliable digital broadband trans.is.ion in the fading wireles. channels.the pres.nce of s.nchro-nization errors.in the form of Carrier Frequency Offs.t(CFO)and Time Offs.t(TO)advers.ly affect the performance of OFDM bas.d phys.cal *** objective of this.work is.to improve the accuracy of the frequency and the time offs.t es.imation in the WiMAX phys.cal layer.A method to enhance the s.nchro-nization accuracy byﬁne-tuning the merit factor of the preamble s.quence is.s.g-ges.ed in this.***,a new preamble with improved s.nchronization accuracy is.propos.d for the WiMAX *** performance of the propos.d preamble is.evaluated in a Rayleigh fading channel and the res.lts.of s.mulations.s.ow that the Mean s.uare Error(Ms.)in offs.t es.imation is.s.gniﬁcantly reduced and it outperforms.the s.andard WiMAX preamble.

关键词： WiMAX MIMO OFDM time offs.t carrier frequency offs.t preamble s.quence integrated s.delobe level merit factor

A Complete Analys.s.of Clarity(C50)Us.ng I-s.MPA to Maintain Ideal Conditions.in an Acous.ic Chamber

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s.und & Vibration 2022年第1期56卷 51-64页

作者： R.Adithya pillai s.s.kthivel Murugan Gurupras.d Gupta Department of Electrical and Electronics.Engineering Sri Sivasubramaniya Nadar College of EngineeringChennai603110India Department of Electronics.and Communication Engineering Sri Sivasubramaniya Nadar College of EngineeringChennai603110India

In any clos.d environment cons.dered,it can be s.en that the acous.ic parameters.are inherently not cons.ant over the entire area *** a clos.d environment,it is.ideally preferred to maintain the acous.ic parameters.as.cons.ant s. that there exis.s.better quality of s.und leading to better auditory perception with res.ect to the ***,s.me of the acous.ic parameters.like reverberation time and clarity do not s.rictly pertain to the pattern obtained *** this.paper,s.mulations.are carried out us.ng I-s.MPA under different values.of s.und Trans.is.ion Clas.(s.C),s.urce pos.tion,dis.ribution and the chamber dimens.ons.and provides.an ins.ght into the behaviour of thes. acous.ic parameters.and the appropriate values.that have to be infus.d into the s.s.em to build the *** acous.ic environment is.modelled keeping an actual clos.d room in mind and tes.ing is.done with res.ect to different values.of s.rface abs.rption coefficients.practically indicated us.ng s.und Trans.is.ion Clas.)and dimens.ons.to determine ideal conditions.

关键词： Clarity C50 s.und s.urce s.rface receiver s.und trans.is.ion clas. s.C s.rface abs.rption percentages

Tight Focus.ng Properties.of Radially Polarized Gaus.ian Beams.with Pair of Vortices

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Chines. Phys.cs.Letters 2016年第12期33卷 73-76页

作者： *** K.B.Rajes. M.Udhayakumar Z.Jaros.ewicz T.V.s.pillai Department of Phys.cs St.Xavier's Catholic College of EngineeringNagercoilIndia Department of Phys.cs Chikkanna Government Arts College Department of Phys.cal Optics Institute of Applied OpticsPolandand National Institute of Telecommunications Department of Phys.cs University College of EngineeringNagercoilIndia

The tight focus.ng properties.of a radially polarized Gaus.ian beam with a nes.ed pair of vortices.having a radial wave front dis.ribution are inves.igated theoretically by the vector diffraction theory. The res.lts.s.ow that the optical intens.ty in the focal region can be altered cons.derably by changing the location of the vortices.nes.ed in a radially polarized Gaus.ian beam. It is.noted that focal evolution from one annular focal pattern to a highly confined focal s.ot in the trans.ers. direction is.obs.rved corres.onding to the change in the location of the optical vortices.in the input plane. It is.als. obs.rved that the generated focal hole or s.ot lead to a focal s.ift along the optical axis.remarkably under proper radial phas. modulation. Hence the propos.d s.s.em may be applied to cons.ruct tunable optical traps.for both high and low refractive index particles.

关键词： of is on in for Tight Focus.ng Properties.of Radially Polarized Gaus.ian Beams.with Pair of Vortices with

Deltamethrin:Promis.ng mos.uito control agent agains. adult s.age of Aedes.aegypti L.

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As.an Pacific Journal of Tropical Medicine 2011年第6期4卷 430-435页

作者： s.rita Kumar Anita Thomas.pillai MKK Department of Zoology Acharya Narendra Dev College(University of Delhi)New Delhi-110019India

Objective:To evaluate the effects.of deltamethrin agains. field-collected adults.of Aedes.aegypti L(***).Methods.The adults.were s.lected with 0.025%deltamethrin for 40 s.cces.ive *** s.lected adults.were tes.ed with 4%DDT and the emerging larvae were tes.ed with various.ins.cticides.to s.udy the cros.-res.s.ance *** knockdown and irritability s.udies.were carried out in adult mos.uitoes.to inves.igate their behavioural res.ons. to ***:Forty generations.of s.lection with deltamethrin res.lted in only 3.8-fold res.s.ance in the adults.of *** adults.of parent(Ps. and s.lected s.rains.(DAs. exhibited only 0.8-fold cros. res.s.ance to 4%*** larvae emerging from the Ps.and DAs.s.rains.did not develop appreciable levels.of res.s.ance to various.ins.cticides.*** knockdown s.udies.revealed KTs. of 14.4 min in Ps.adults.with no s.gns.of recovery even after 24 h. The DAs.s.rains.could develop only 1.2 to 1.3-fold knockdown res.s.ance(KDR).The knockdown res.ons. of DDT was.though 5-6 times.s.ower than deltamethrin but the continued res.ons. in deltamethrin-s.lected adults.caus.d only 1.2-fold *** Ps.and DAs.s.rains.exhibited s.gnificant irritability res.ons. towards.deltamethrin and *** DAs.s.rains.s.owed 5-6 fold increas.d irritability to deltamethrin as.compared to the Ps.***:The above res.lts.s.gges. the prolonged effective us. of deltamethrin agains. *** as.an adulticide.

关键词： Deltamethrin Knockdown Irritability Res.s.ance Cros.-res.s.ance