CISM International Centre for Mechanical Sciences 571 Courses and Lectures Jean-Pierre Minier Jacek Pozorski E ditors Particles in Wall- Bounded Turbulent Flows: Deposition, Re-Suspension and Agglomeration International Centre for Mechanical Sciences CISM International Centre for Mechanical Sciences Courses and Lectures Volume 571 Series editors The Rectors Friedrich Pfeiffer, Munich, Germany Franz G. Rammerstorfer, Vienna, Austria Elisabeth Guazzelli, Marseille, France The Secretary General Bernhard Schrefler, Padua, Italy Executive Editor Paolo Serafini, Udine, Italy Theseriespresentslecturenotes,monographs,editedworksandproceedingsinthe field of Mechanics, Engineering, Computer Science and Applied Mathematics. Purpose of the series is to make known in the international scientific and technical community results obtained in some of the activities organized by CISM, the International Centre for Mechanical Sciences. More information about this series at http://www.springer.com/series/76 Jean-Pierre Minier Jacek Pozorski (cid:129) Editors Particles in Wall-Bounded Turbulent Flows: Deposition, Re-Suspension and Agglomeration 123 Editors Jean-Pierre Minier JacekPozorski MFEE Institute of Fluid-Flow Machinery EDFResearch & Development Polish Academy ofSciences Chatou Gdansk France Poland ISSN 0254-1971 ISSN 2309-3706 (electronic) CISMInternational Centre for MechanicalSciences ISBN978-3-319-41566-6 ISBN978-3-319-41567-3 (eBook) DOI 10.1007/978-3-319-41567-3 LibraryofCongressControlNumber:2016943322 ©CISMInternationalCentreforMechanicalSciences2017 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpart of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission orinformationstorageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilar methodologynowknownorhereafterdeveloped. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publicationdoesnotimply,evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfrom therelevantprotectivelawsandregulationsandthereforefreeforgeneraluse. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authorsortheeditorsgiveawarranty,expressorimplied,withrespecttothematerialcontainedhereinor foranyerrorsoromissionsthatmayhavebeenmade. Printedonacid-freepaper ThisSpringerimprintispublishedbySpringerNature TheregisteredcompanyisSpringerInternationalPublishingAGSwitzerland Preface The chapters contained in this volume correspond to the lectures given during the course “Particles in wall-bounded turbulent flows: deposition, resuspension and agglomeration” that was held at the CISM, Udine (Italy), 14–18 September 2015. The subject of particle dynamics in turbulent flows is a rich and diverse one, especially in the case of turbulent boundary layers. As indicated by the subtitle of the course, this issue was addressed with a view towards the theme of particle deposition.Thisgeneralterminologyincludesacomplex arrayofphenomenasuch asdepositionofparticlesonwallsbutalsoresuspensionandagglomeration.Thisis an intricate field involving an interplay between particle transport by turbulent flows, adhesion forces as well as material properties. This is also an interdisci- plinary subject where numerical investigations complete experimental studies and help to develop models at various levels of description. This volume starts with a general introduction to particle deposition by Jean-Pierre Minier. It is followed by a presentation of the experimental techniques neededtoanalysethephysicsinvolvedbyRenévanHout.Themodellingaspectsof turbulentflowsandparticledynamicsarediscussedbyJacekPozorski.Thechapter written by Cristian Marchioli details the physical picture of particle transport in near-wallboundarylayersrevealedinrecentyearsbydirectnumericalsimulations. Thecomplementaryaspectofadhesionforcesbetweenparticlesandsurfacesthatis importantinparticledepositioniscoveredinthelastchapterbyChristopheHenry. It is therefore believed that the present volume offers an up-to-date and com- prehensiveoverview ofthevariousphenomenaplayingarole inparticle dynamics in wall-bounded flows and particle deposition. Chatou, France Jean-Pierre Minier Gdansk, Poland Jacek Pozorski v Contents A General Introduction to Particle Deposition . . . . . . . . . . . . . . . . . . . 1 Jean-Pierre Minier Using Holography and Particle Image Velocimetry to Study Particle Deposition, Re-suspension and Agglomeration . . . . . . . . . . . . . 37 René van Hout Models of Turbulent Flows and Particle Dynamics. . . . . . . . . . . . . . . . 97 Jacek Pozorski Physics and Modelling of Particle Deposition and Resuspension in Wall-Bounded Turbulence. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151 Cristian Marchioli Surface Forces and Their Application to Particle Deposition and Resuspension. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209 Christophe Henry vii A General Introduction to Particle Deposition Jean-PierreMinier Abstract Thepurposeofthischapteristoprovideanintroductiontothethemeof particle deposition and, in that sense, tothe various contributions compiled in this book. Thisisdone bypresenting various examples whicharehelpful toreveal the diversitythroughwhichparticledepositionismanifested.Thissurveyisalsouseful to clarify the aspects that are addressed and those that are outside of the present scope.Basedonthisoverview, aframeworkisproposedwhereparticledeposition is decomposed in elementary phenomena and fundamental interactions. Then, the characteristic rates of deposition, resuspension and agglomeration are introduced. As the phenomena making up particle deposition can be addressed from different modellingstandpoints,thenotionofmicroscopic,mesoscopicandmacroscopiclev- els of description is introduced and the relations between these different points of viewissketched. 1 Introduction Generally speaking, particle deposition can be regarded as the accumulation of ‘material’ (meaning here discrete particles) on solid walls, or similar boundaries, containingaliquidorgasflowintowhichtheseparticlesareinitiallyembedded.As such, particle deposition appears as a common-enough term and does not seem to requiretoolonganintroduction.Yet,theubiquitousnatureoftheprocessofparti- cledepositioncanleadtosomeuncertainty,ifnottosomeconfusion,astowhatis exactly involved and as to the specific physical mechanisms involved. First of all, this is reflected in the variety of terms that are used. For example, particle depo- sitioncanbereferredtoasdepositionorfouling;particleresuspensionasremoval or re-entrainment; whereas agglomeration can be described also as aggregation, flocculation,coagulation,coalescence,etc.Second,thereisnotalwaysaclearand immediateindicationonwhethertheseeffectsaredesirableandthereforepromoted B J.-P.Minier ( ) MFEE,EDFR&D,6QuaiWatier,78400Chatou,France e-mail:[email protected] ©CISMInternationalCentreforMechanicalSciences2017 1 J.-P.MinierandJ.Pozorski(eds.),ParticlesinWall-BoundedTurbulentFlows: Deposition,Re-SuspensionandAgglomeration,CISMInternationalCentre forMechanicalSciences571,DOI10.1007/978-3-319-41567-3_1 2 J.-P.Minier orundesirableandthuspreventedfromhappening.Finally,thephysicalmechanisms andinteractionsineachsituationarenotnecessarilythesame. Itisthusimportanttogiveanswerstothefollowingquestions: (1) Whatdoesthepresentnotionof‘particledeposition’correspondto? (2) Whatarethephysicalmechanismsinvolved? (3) Whatarethefundamentalphysicalinteractionsatplay? Answers to these queries can be provided by considering typical practical situ- ations concerned with this issue, before going into a more detailed analysis of the physicalmechanismsandinteractionsinthenexttwosections. 2 OverviewofSituationsInvolvingParticleDeposition To start with, we consider a situation where particle deposition and resuspension have an effect on human health and the environment, as depicted in Fig.1. It can beseenthat,first,suchquestionsarisenaturallyinthecontextofthegrowingcon- cerns about the interaction between natural or human-induced processes (such as road traffic in the present example) and possible health hazards and, second, that suchreal-lifesituationinvolvescomplexandcoupledphenomena.Theparticlessub- jecttodepositionandresuspensioncancomefromverydifferentsourcesandhave differentcharacteristics(dust,ice,aerosols,etc.,evenvariousdebris).Withrespect to the terminology used in this application, it can be noted that the term removal is used instead of resuspension with re-entrainment used for one process (namely car-inducedresuspension)whiledepositionreferstothemotionofparticlesfromthe surroundingairtowardsthegroundandnottotheresultingbalancebetweenthetwo competingprocessesofdepositionandremoval.Itisalsorelevanttonotethatboth depositionandremovalareduetoenvironmentalflows(winderosionorwindmotion towardtheground)aswellastohumanactivities(re-entrainmentduetofluidflow inthewakeofpassingvehiclesordebrisinducedbyalawnmower).Furthermore, the scales involved can cover several orders of magnitude, from the typical scales ofthenear-groundatmosphericboundarylayertohumansizeandevensmaller.As summarised by the question in the header of Fig.1, the challenge is to model and simulate such a complex situation. In turn, this requires to understand the physics governing theseparatebasicphenomena andtocapture theiressentialcharacteris- ticsinamodellingapproachthatremainstractableforpracticalconcernsincomplex geometries. A second illustration concerns the classical notion of the stability of colloidal suspensions (seedetailed accounts inreference textbooks on colloids,for instance Elimelechetal.1995;Hunter2001;Israelachvili2011).AssketchedinFig.2,col- loids(whichcanbeunderstoodhereassmallparticleswithdiametersoftheorder of one micron) are first dispersed in a liquid medium at rest in a container. In the firstsituationrepresentedinFig.2,thechemicalconditionsaresuchthatthesecol- loidsrepeleachotherand,astheirdiameterissmallenoughforthegravityforceto AGeneralIntroductiontoParticleDeposition 3 Fig.1 Sketchofenvironmental-relatedconcernsinvolvingparticledepositionandresuspensionin acomplexsituationforroadtrafficissues Fig.2 Stabilityofcolloidsuspensions:aschemicalconditionsarechangedintheliquidmedium, astablesuspensioncanbecomeunstablewithcolloidagglomeratesdepositingonthebottomwall be counter-balanced by Brownian motion, they do not deposit on the bottom wall ofthecontainer:thecolloidalsuspensionisthensaidtobestable.However,when thechemicalconditionsarechangedintheliquid,attractiveforcesbetweencolloids canovercomerepulsiveonesleadingtotheformationofagglomerates.Ascolloids agglomerate,thediameteroftheresultingaggregatesgrowsandcanbecomelarge enoughforthegravityforcetoinduceadownwardmotiontowardsthebottomwall: the solution is then said to be unstable. As a result of this agglomeration process, particles(meaninghereagglomeratesoftheinitialcolloids)depositonthebottom wall of the container and, since this deposition process is governed by gravity, it is referred to as ‘sedimentation’. In this example, it is important to note that the fluidisatacompletestandstillandthatdepositionisnottheresultoffluidmotions.