{"id":{"repo_id":"aalto","oai_identifier":"oai:aaltodoc.aalto.fi:123456789/18206"},"canonical_url":"https://search.dev.ndltd.org/etd/aalto/oai:aaltodoc.aalto.fi:123456789/18206","repository":{"repo_id":"aalto","name":"Aalto University","base_url":"https://aaltodoc.aalto.fi/server/oai/request"},"display":{"title":"Spatially resolved rheology modeling of complex fluids","abstract":"Many complex fluids show yield stress behavior. However, the term yield stress has been subject of much controversy. The separation of yield stress fluids into thixotropic and simple ones resolves many of these issues. This division is mainly driven by experimental results and is suspect to active theoretical development. This thesis addresses yield stress fluids and associated phenomena through continuum modeling for fluids with time dependent structure evolution. In addition to homogeneous laminar shear modeling, the emergence of spatial effects in viscometric flow situations is addressed. Therefore the models are coupled to the creeping flow solution (1-D Stokes equation) of a concentric cylinder geometry, which enables comparisons with experimental observations. Further, the results from thixotropic yield stress fluids are applied to the analysis of rheology measurements of nanocellulose suspensions, which have peculiar rheological properties. In particular, shear rate sweeps are simulated utilizing a structural model for thixotropic yield stress fluids. The results indicate that spatial flow heterogeneities have to be taken into account. Additionally wall slip, which is known to play an important role in the flow of complex fluids is addressed through a simple model. The results in this thesis add to the understanding of nanocellulose suspensions and complex fluids in general.","abstract_html":"Many complex fluids show yield stress behavior. However, the term yield stress has been subject of much controversy. The separation of yield stress fluids into thixotropic and simple ones resolves many of these issues. This division is mainly driven by experimental results and is suspect to active theoretical development. This thesis addresses yield stress fluids and associated phenomena through continuum modeling for fluids with time dependent structure evolution. In addition to homogeneous laminar shear modeling, the emergence of spatial effects in viscometric flow situations is addressed. Therefore the models are coupled to the creeping flow solution (1-D Stokes equation) of a concentric cylinder geometry, which enables comparisons with experimental observations. Further, the results from thixotropic yield stress fluids are applied to the analysis of rheology measurements of nanocellulose suspensions, which have peculiar rheological properties. In particular, shear rate sweeps are simulated utilizing a structural model for thixotropic yield stress fluids. The results indicate that spatial flow heterogeneities have to be taken into account. Additionally wall slip, which is known to play an important role in the flow of complex fluids is addressed through a simple model. The results in this thesis add to the understanding of nanocellulose suspensions and complex fluids in general.","abstract_has_math":false,"creators":["Mohtaschemi, Mikael"],"institution":"Aalto University","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":"Teknillisen fysiikan laitos","school":null,"contributors":["Aalto-yliopisto","Aalto University"],"advisors":["Puisto, Antti, Dr., Aalto University, Department of Applied Physics, Finland","Alava, Mikko, Prof., Aalto University, Department of Applied Physics, Finland"],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015","date_published":"2015","updated_at":"2026-08-21T22:21:56Z","subjects":[],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://aaltodoc.aalto.fi/handle/123456789/18206","outbound_label":"Repository record","outbound_source":"dc:identifier.uri"},"source_record":{"url":"https://aaltodoc.aalto.fi/server/oai/request?verb=GetRecord&metadataPrefix=dim&identifier=oai%3Aaaltodoc.aalto.fi%3A123456789%2F18206","prefix":"dim"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Aalto-yliopisto","Aalto University"]},{"key":"dc:contributor.advisor","label":"Advisor","values":["Puisto, Antti, Dr., Aalto University, Department of Applied Physics, Finland"]},{"key":"dc:contributor.department","label":"Department","values":["Teknillisen fysiikan laitos","Department of Applied Physics"]},{"key":"dc:contributor.supervisor","label":"Supervisor","values":["Alava, Mikko, Prof., Aalto University, Department of Applied Physics, Finland"]},{"key":"dc:creator","label":"Author","values":["Mohtaschemi, Mikael"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2015-10-27T10:01:54Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2015-10-27T10:01:54Z"]},{"key":"dc:date.issued","label":"Date","values":["2015"]},{"key":"dc:publisher","label":"Institution","values":["Aalto University","Aalto-yliopisto"]},{"key":"dc:type","label":"Dc Type","values":["G5 Artikkeliväitöskirja"]},{"key":"dc:type.dcmitype","label":"Dc Type Dcmitype","values":["text"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://aaltodoc.aalto.fi/handle/123456789/18206"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Many complex fluids show yield stress behavior. However, the term yield stress has been subject of much controversy. The separation of yield stress fluids into thixotropic and simple ones resolves many of these issues. This division is mainly driven by experimental results and is suspect to active theoretical development. This thesis addresses yield stress fluids and associated phenomena through continuum modeling for fluids with time dependent structure evolution. In addition to homogeneous laminar shear modeling, the emergence of spatial effects in viscometric flow situations is addressed. Therefore the models are coupled to the creeping flow solution (1-D Stokes equation) of a concentric cylinder geometry, which enables comparisons with experimental observations. Further, the results from thixotropic yield stress fluids are applied to the analysis of rheology measurements of nanocellulose suspensions, which have peculiar rheological properties. In particular, shear rate sweeps are simulated utilizing a structural model for thixotropic yield stress fluids. The results indicate that spatial flow heterogeneities have to be taken into account. Additionally wall slip, which is known to play an important role in the flow of complex fluids is addressed through a simple model. The results in this thesis add to the understanding of nanocellulose suspensions and complex fluids in general.","Vaikka monilla kompleksisilla nesteillä on tunnetusti myötöraja, kyseiseen käsitteeseen ja sen määrittelyyn on kuitenkin liittynyt paljon ristiriitoja. Jakamalla myötörajanesteet yksinkertaisiin sekä tiksotrooppisiin, monet käsitteelliset ongelmat poistuvat. Tämä jako on toistaiseksi pitkälti kokeellisten tulosten varassa ja siihen liittyvä teoria on aktiivisen kehityksen alla. Tämä väitöskirja käsittelee myötörajaa ja siihen liittyviä ilmiöitä jatkumotason malleilla sellaisille nesteille, joilla on ajassa kehittyvä rakenne. Homogeenisen, laminaarisen leikkausvirtauksen lisäksi käsitellään spatiaalisten ilmiöiden syntyä. Tätä varten mallit yhdistetään sylinteri-sylinteri geometrian yksiulotteisen Stokesin virtauksen ratkaisuun mahdollistaen samalla vertailun kokeellisten havaintojen kanssa. Tiksotrooppisten myötörajanesteiden tuloksia sovelletaan nanoselluloosasuspensioden reologian analysointiin. Näiden suspensioden kokeellisia leikkausvirtauspyyhkäisyjä simuloidaan tiksotrooppisella rakennemallilla. Tulosten perusteella virtauksen geometrisiä epähomogenisuuksia on otettava huomioon. Lisäksi kokeellisesti tärkeäksi havaittua liusumisilmiöta (wall slip), käsitellään yksinkertaisen mallin avulla. Tämän väitöskirjan tulokset edistävät nanoselluloosasuspensioden sekä yleisesti kompleksisten nesteiden ymmärrystä."]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Spatially resolved rheology modeling of complex fluids","Kompleksisten nesteiden spatiaalinen reologiamallinnus"]}]}],"canonical_facts":{"dc:contributor":["Aalto-yliopisto","Aalto University"],"dc:contributor.advisor":["Puisto, Antti, Dr., Aalto University, Department of Applied Physics, Finland"],"dc:contributor.department":["Teknillisen fysiikan laitos","Department of Applied Physics"],"dc:contributor.supervisor":["Alava, Mikko, Prof., Aalto University, Department of Applied Physics, Finland"],"dc:creator":["Mohtaschemi, Mikael"],"dc:date.accessioned":["2015-10-27T10:01:54Z"],"dc:date.available":["2015-10-27T10:01:54Z"],"dc:date.issued":["2015"],"dc:description.abstract":["Many complex fluids show yield stress behavior. However, the term yield stress has been subject of much controversy. The separation of yield stress fluids into thixotropic and simple ones resolves many of these issues. This division is mainly driven by experimental results and is suspect to active theoretical development. This thesis addresses yield stress fluids and associated phenomena through continuum modeling for fluids with time dependent structure evolution. In addition to homogeneous laminar shear modeling, the emergence of spatial effects in viscometric flow situations is addressed. Therefore the models are coupled to the creeping flow solution (1-D Stokes equation) of a concentric cylinder geometry, which enables comparisons with experimental observations. Further, the results from thixotropic yield stress fluids are applied to the analysis of rheology measurements of nanocellulose suspensions, which have peculiar rheological properties. In particular, shear rate sweeps are simulated utilizing a structural model for thixotropic yield stress fluids. The results indicate that spatial flow heterogeneities have to be taken into account. Additionally wall slip, which is known to play an important role in the flow of complex fluids is addressed through a simple model. The results in this thesis add to the understanding of nanocellulose suspensions and complex fluids in general.","Vaikka monilla kompleksisilla nesteillä on tunnetusti myötöraja, kyseiseen käsitteeseen ja sen määrittelyyn on kuitenkin liittynyt paljon ristiriitoja. Jakamalla myötörajanesteet yksinkertaisiin sekä tiksotrooppisiin, monet käsitteelliset ongelmat poistuvat. Tämä jako on toistaiseksi pitkälti kokeellisten tulosten varassa ja siihen liittyvä teoria on aktiivisen kehityksen alla. Tämä väitöskirja käsittelee myötörajaa ja siihen liittyviä ilmiöitä jatkumotason malleilla sellaisille nesteille, joilla on ajassa kehittyvä rakenne. Homogeenisen, laminaarisen leikkausvirtauksen lisäksi käsitellään spatiaalisten ilmiöiden syntyä. Tätä varten mallit yhdistetään sylinteri-sylinteri geometrian yksiulotteisen Stokesin virtauksen ratkaisuun mahdollistaen samalla vertailun kokeellisten havaintojen kanssa. Tiksotrooppisten myötörajanesteiden tuloksia sovelletaan nanoselluloosasuspensioden reologian analysointiin. Näiden suspensioden kokeellisia leikkausvirtauspyyhkäisyjä simuloidaan tiksotrooppisella rakennemallilla. Tulosten perusteella virtauksen geometrisiä epähomogenisuuksia on otettava huomioon. Lisäksi kokeellisesti tärkeäksi havaittua liusumisilmiöta (wall slip), käsitellään yksinkertaisen mallin avulla. Tämän väitöskirjan tulokset edistävät nanoselluloosasuspensioden sekä yleisesti kompleksisten nesteiden ymmärrystä."],"dc:format.mimetype":["application/pdf"],"dc:identifier.uri":["https://aaltodoc.aalto.fi/handle/123456789/18206"],"dc:language.iso":["en"],"dc:publisher":["Aalto University","Aalto-yliopisto"],"dc:title":["Spatially resolved rheology modeling of complex fluids","Kompleksisten nesteiden spatiaalinen reologiamallinnus"],"dc:type":["G5 Artikkeliväitöskirja"],"dc:type.dcmitype":["text"]},"updated_at":"2026-08-21T22:21:56Z"}