The wake behind a cylinder rolling on a wall at varying rotation rates
Identifieur interne : 002688 ( PascalFrancis/Corpus ); précédent : 002687; suivant : 002689The wake behind a cylinder rolling on a wall at varying rotation rates
Auteurs : B. E. Stewart ; M. C. Thompson ; T. Leweke ; K. HouriganSource :
- Journal of Fluid Mechanics [ 0022-1120 ] ; 2010.
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- Pascal (Inist)
English descriptors
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Abstract
A study investigating the flow around a cylinder rolling or sliding on a wall has been undertaken in two and three dimensions. The cylinder motion is specified from a set of five discrete rotation rates, ranging from prograde through to retrograde rolling. A Reynolds number range of 20-500 is considered. The effects of the nearby wall and the imposed body motion on the wake structure and dominant wake transitions have been determined. Prograde rolling is shown to destabilize the wake flow, while retrograde rotation delays the onset of unsteady flow to Reynolds numbers well above those observed for a cylinder in an unbounded flow. Two-dimensional simulations show the presence of two recirculation zones in the steady wake, the lengths of which increase approximately linearly with the Reynolds number. Values of the lift and drag coefficient are also reported for the steady flow regime. Results from a linear stability analysis show that the wake initially undergoes a regular bifurcation from a steady two-dimensional flow to a steady three-dimensional wake for all rotation rates. The critical Reynolds number Rec of transition and the spanwise wavelength of the dominant mode are shown to be highly dependent on, but smoothly varying with, the rotation rate of the cylinder. Varying the rotation from prograde to retrograde rolling acts to increase the value of Rec and decrease the preferred wavelength. The structure of the fully evolved wake mode is then established through three-dimensional simulations. In fact it is found that at Reynolds numbers only marginally (∼5 %) above critical, the three-dimensional simulations indicate that the saturated state becomes time dependent, although at least initially, this does not result in a significant change to the mode structure. It is only at higher Reynolds numbers that the wake undergoes a transition to vortex shedding. An analysis of the three-dimensional transition indicates that it is unlikely to be due to a centrifugal instability despite the superficial similarity to the flow over a backward-facing step, for which the transition mechanism has been speculated to be centrifugal. However, the attached elongated recirculation region and distribution of the spanwise perturbation vorticity field, and the similarity of these features with those of the flow through a partially blocked channel, suggest the possibility that the mechanism is elliptic in nature. Some analysis which supports this conjecture is undertaken.
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| NO : | PASCAL 10-0248008 INIST |
|---|---|
| ET : | The wake behind a cylinder rolling on a wall at varying rotation rates |
| AU : | STEWART (B. E.); THOMPSON (M. C.); LEWEKE (T.); HOURIGAN (K.) |
| AF : | Fluids Laboratory for Aeronautical and Industrial Research (FLAIR), Department of Mechanical and Aerospace Engineering, Monash University/Melbourne, Victoria 3800/Australie (1 aut., 2 aut., 4 aut.); Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), CNRS/Universités Aix-Marseille, 49 rue Frédéric Joliot-Curie, BP 146/13384 Marseille/France (1 aut., 3 aut.); Division of Biological Engineering, Monash University/Melbourne, Victoria 3800/Australie (4 aut.) |
| DT : | Publication en série; Niveau analytique |
| SO : | Journal of Fluid Mechanics; ISSN 0022-1120; Coden JFLSA7; Royaume-Uni; Da. 2010; Vol. 648; Pp. 225-256; Bibl. 2 p. |
| LA : | Anglais |
| EA : | A study investigating the flow around a cylinder rolling or sliding on a wall has been undertaken in two and three dimensions. The cylinder motion is specified from a set of five discrete rotation rates, ranging from prograde through to retrograde rolling. A Reynolds number range of 20-500 is considered. The effects of the nearby wall and the imposed body motion on the wake structure and dominant wake transitions have been determined. Prograde rolling is shown to destabilize the wake flow, while retrograde rotation delays the onset of unsteady flow to Reynolds numbers well above those observed for a cylinder in an unbounded flow. Two-dimensional simulations show the presence of two recirculation zones in the steady wake, the lengths of which increase approximately linearly with the Reynolds number. Values of the lift and drag coefficient are also reported for the steady flow regime. Results from a linear stability analysis show that the wake initially undergoes a regular bifurcation from a steady two-dimensional flow to a steady three-dimensional wake for all rotation rates. The critical Reynolds number Rec of transition and the spanwise wavelength of the dominant mode are shown to be highly dependent on, but smoothly varying with, the rotation rate of the cylinder. Varying the rotation from prograde to retrograde rolling acts to increase the value of Rec and decrease the preferred wavelength. The structure of the fully evolved wake mode is then established through three-dimensional simulations. In fact it is found that at Reynolds numbers only marginally (∼5 %) above critical, the three-dimensional simulations indicate that the saturated state becomes time dependent, although at least initially, this does not result in a significant change to the mode structure. It is only at higher Reynolds numbers that the wake undergoes a transition to vortex shedding. An analysis of the three-dimensional transition indicates that it is unlikely to be due to a centrifugal instability despite the superficial similarity to the flow over a backward-facing step, for which the transition mechanism has been speculated to be centrifugal. However, the attached elongated recirculation region and distribution of the spanwise perturbation vorticity field, and the similarity of these features with those of the flow through a partially blocked channel, suggest the possibility that the mechanism is elliptic in nature. Some analysis which supports this conjecture is undertaken. |
| CC : | 001B40G32F |
| FD : | Ecoulement instationnaire; Ecoulement tourbillonnaire; Détachement tourbillonnaire; Sillage; Cylindre tournant; Génération maille; Modélisation; Simulation numérique; Visualisation écoulement; Contact roulant glissant; Translation; Vorticité; Coefficient portance; 4732F |
| ED : | Unsteady flow; Vortex flow; Vortex shedding; Wakes; Rotating cylinder; Mesh generation; Modelling; Digital simulation; Flow visualization; Rolling sliding contact; Translation; Vorticity; Lift coefficient |
| SD : | Desprendimiento vorticial; Cilindro rotativo; Contacto rodante deslizante; Coeficiente sustentador |
| LO : | INIST-5180.354000180606410100 |
| ID : | 10-0248008 |
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Thompson</name><affiliation><inist:fA14 i1="01"><s1>Fluids Laboratory for Aeronautical and Industrial Research (FLAIR), Department of Mechanical and Aerospace Engineering, Monash University</s1><s2>Melbourne, Victoria 3800</s2><s3>AUS</s3><sZ>1 aut.</sZ><sZ>2 aut.</sZ><sZ>4 aut.</sZ></inist:fA14></affiliation></author><author><name sortKey="Leweke, T" sort="Leweke, T" uniqKey="Leweke T" first="T." last="Leweke">T. Leweke</name><affiliation><inist:fA14 i1="02"><s1>Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), CNRS/Universités Aix-Marseille, 49 rue Frédéric Joliot-Curie, BP 146</s1><s2>13384 Marseille</s2><s3>FRA</s3><sZ>1 aut.</sZ><sZ>3 aut.</sZ></inist:fA14></affiliation></author><author><name sortKey="Hourigan, K" sort="Hourigan, K" uniqKey="Hourigan K" first="K." last="Hourigan">K. Hourigan</name><affiliation><inist:fA14 i1="01"><s1>Fluids Laboratory for Aeronautical and Industrial Research (FLAIR), Department of Mechanical and Aerospace Engineering, Monash University</s1><s2>Melbourne, Victoria 3800</s2><s3>AUS</s3><sZ>1 aut.</sZ><sZ>2 aut.</sZ><sZ>4 aut.</sZ></inist:fA14></affiliation><affiliation><inist:fA14 i1="03"><s1>Division of Biological Engineering, Monash University</s1><s2>Melbourne, Victoria 3800</s2><s3>AUS</s3><sZ>4 aut.</sZ></inist:fA14></affiliation></author></titleStmt><publicationStmt><idno type="wicri:source">INIST</idno><idno type="inist">10-0248008</idno><date when="2010">2010</date><idno type="stanalyst">PASCAL 10-0248008 INIST</idno><idno type="RBID">Pascal:10-0248008</idno><idno type="wicri:Area/PascalFrancis/Corpus">002688</idno></publicationStmt><sourceDesc><biblStruct><analytic><title xml:lang="en" level="a">The wake behind a cylinder rolling on a wall at varying rotation rates</title><author><name sortKey="Stewart, B E" sort="Stewart, B E" uniqKey="Stewart B" first="B. E." last="Stewart">B. E. Stewart</name><affiliation><inist:fA14 i1="01"><s1>Fluids Laboratory for Aeronautical and Industrial Research (FLAIR), Department of Mechanical and Aerospace Engineering, Monash University</s1><s2>Melbourne, Victoria 3800</s2><s3>AUS</s3><sZ>1 aut.</sZ><sZ>2 aut.</sZ><sZ>4 aut.</sZ></inist:fA14></affiliation><affiliation><inist:fA14 i1="02"><s1>Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), CNRS/Universités Aix-Marseille, 49 rue Frédéric Joliot-Curie, BP 146</s1><s2>13384 Marseille</s2><s3>FRA</s3><sZ>1 aut.</sZ><sZ>3 aut.</sZ></inist:fA14></affiliation></author><author><name sortKey="Thompson, M C" sort="Thompson, M C" uniqKey="Thompson M" first="M. C." last="Thompson">M. C. Thompson</name><affiliation><inist:fA14 i1="01"><s1>Fluids Laboratory for Aeronautical and Industrial Research (FLAIR), Department of Mechanical and Aerospace Engineering, Monash University</s1><s2>Melbourne, Victoria 3800</s2><s3>AUS</s3><sZ>1 aut.</sZ><sZ>2 aut.</sZ><sZ>4 aut.</sZ></inist:fA14></affiliation></author><author><name sortKey="Leweke, T" sort="Leweke, T" uniqKey="Leweke T" first="T." last="Leweke">T. Leweke</name><affiliation><inist:fA14 i1="02"><s1>Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), CNRS/Universités Aix-Marseille, 49 rue Frédéric Joliot-Curie, BP 146</s1><s2>13384 Marseille</s2><s3>FRA</s3><sZ>1 aut.</sZ><sZ>3 aut.</sZ></inist:fA14></affiliation></author><author><name sortKey="Hourigan, K" sort="Hourigan, K" uniqKey="Hourigan K" first="K." last="Hourigan">K. Hourigan</name><affiliation><inist:fA14 i1="01"><s1>Fluids Laboratory for Aeronautical and Industrial Research (FLAIR), Department of Mechanical and Aerospace Engineering, Monash University</s1><s2>Melbourne, Victoria 3800</s2><s3>AUS</s3><sZ>1 aut.</sZ><sZ>2 aut.</sZ><sZ>4 aut.</sZ></inist:fA14></affiliation><affiliation><inist:fA14 i1="03"><s1>Division of Biological Engineering, Monash University</s1><s2>Melbourne, Victoria 3800</s2><s3>AUS</s3><sZ>4 aut.</sZ></inist:fA14></affiliation></author></analytic><series><title level="j" type="main">Journal of Fluid Mechanics</title><title level="j" type="abbreviated">J. Fluid Mech.</title><idno type="ISSN">0022-1120</idno><imprint><date when="2010">2010</date></imprint></series></biblStruct></sourceDesc><seriesStmt><title level="j" type="main">Journal of Fluid Mechanics</title><title level="j" type="abbreviated">J. Fluid Mech.</title><idno type="ISSN">0022-1120</idno></seriesStmt></fileDesc><profileDesc><textClass><keywords scheme="KwdEn" xml:lang="en"><term>Digital simulation</term><term>Flow visualization</term><term>Lift coefficient</term><term>Mesh generation</term><term>Modelling</term><term>Rolling sliding contact</term><term>Rotating cylinder</term><term>Translation</term><term>Unsteady flow</term><term>Vortex flow</term><term>Vortex shedding</term><term>Vorticity</term><term>Wakes</term></keywords><keywords scheme="Pascal" xml:lang="fr"><term>Ecoulement instationnaire</term><term>Ecoulement tourbillonnaire</term><term>Détachement tourbillonnaire</term><term>Sillage</term><term>Cylindre tournant</term><term>Génération maille</term><term>Modélisation</term><term>Simulation numérique</term><term>Visualisation écoulement</term><term>Contact roulant glissant</term><term>Translation</term><term>Vorticité</term><term>Coefficient portance</term><term>4732F</term></keywords></textClass></profileDesc></teiHeader><front><div type="abstract" xml:lang="en">A study investigating the flow around a cylinder rolling or sliding on a wall has been undertaken in two and three dimensions. The cylinder motion is specified from a set of five discrete rotation rates, ranging from prograde through to retrograde rolling. A Reynolds number range of 20-500 is considered. The effects of the nearby wall and the imposed body motion on the wake structure and dominant wake transitions have been determined. Prograde rolling is shown to destabilize the wake flow, while retrograde rotation delays the onset of unsteady flow to Reynolds numbers well above those observed for a cylinder in an unbounded flow. Two-dimensional simulations show the presence of two recirculation zones in the steady wake, the lengths of which increase approximately linearly with the Reynolds number. Values of the lift and drag coefficient are also reported for the steady flow regime. Results from a linear stability analysis show that the wake initially undergoes a regular bifurcation from a steady two-dimensional flow to a steady three-dimensional wake for all rotation rates. The critical Reynolds number Re<sub>c</sub> of transition and the spanwise wavelength of the dominant mode are shown to be highly dependent on, but smoothly varying with, the rotation rate of the cylinder. Varying the rotation from prograde to retrograde rolling acts to increase the value of Re<sub>c</sub> and decrease the preferred wavelength. The structure of the fully evolved wake mode is then established through three-dimensional simulations. In fact it is found that at Reynolds numbers only marginally (∼5 %) above critical, the three-dimensional simulations indicate that the saturated state becomes time dependent, although at least initially, this does not result in a significant change to the mode structure. It is only at higher Reynolds numbers that the wake undergoes a transition to vortex shedding. An analysis of the three-dimensional transition indicates that it is unlikely to be due to a centrifugal instability despite the superficial similarity to the flow over a backward-facing step, for which the transition mechanism has been speculated to be centrifugal. However, the attached elongated recirculation region and distribution of the spanwise perturbation vorticity field, and the similarity of these features with those of the flow through a partially blocked channel, suggest the possibility that the mechanism is elliptic in nature. Some analysis which supports this conjecture is undertaken.</div></front></TEI><inist><standard h6="B"><pA><fA01 i1="01" i2="1"><s0>0022-1120</s0></fA01><fA02 i1="01"><s0>JFLSA7</s0></fA02><fA03 i2="1"><s0>J. Fluid Mech.</s0></fA03><fA05><s2>648</s2></fA05><fA08 i1="01" i2="1" l="ENG"><s1>The wake behind a cylinder rolling on a wall at varying rotation rates</s1></fA08><fA11 i1="01" i2="1"><s1>STEWART (B. E.)</s1></fA11><fA11 i1="02" i2="1"><s1>THOMPSON (M. C.)</s1></fA11><fA11 i1="03" i2="1"><s1>LEWEKE (T.)</s1></fA11><fA11 i1="04" i2="1"><s1>HOURIGAN (K.)</s1></fA11><fA14 i1="01"><s1>Fluids Laboratory for Aeronautical and Industrial Research (FLAIR), Department of Mechanical and Aerospace Engineering, Monash University</s1><s2>Melbourne, Victoria 3800</s2><s3>AUS</s3><sZ>1 aut.</sZ><sZ>2 aut.</sZ><sZ>4 aut.</sZ></fA14><fA14 i1="02"><s1>Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), CNRS/Universités Aix-Marseille, 49 rue Frédéric Joliot-Curie, BP 146</s1><s2>13384 Marseille</s2><s3>FRA</s3><sZ>1 aut.</sZ><sZ>3 aut.</sZ></fA14><fA14 i1="03"><s1>Division of Biological Engineering, Monash University</s1><s2>Melbourne, Victoria 3800</s2><s3>AUS</s3><sZ>4 aut.</sZ></fA14><fA20><s1>225-256</s1></fA20><fA21><s1>2010</s1></fA21><fA23 i1="01"><s0>ENG</s0></fA23><fA43 i1="01"><s1>INIST</s1><s2>5180</s2><s5>354000180606410100</s5></fA43><fA44><s0>0000</s0><s1>© 2010 INIST-CNRS. All rights reserved.</s1></fA44><fA45><s0>2 p.</s0></fA45><fA47 i1="01" i2="1"><s0>10-0248008</s0></fA47><fA60><s1>P</s1></fA60><fA61><s0>A</s0></fA61><fA64 i1="01" i2="1"><s0>Journal of Fluid Mechanics</s0></fA64><fA66 i1="01"><s0>GBR</s0></fA66><fC01 i1="01" l="ENG"><s0>A study investigating the flow around a cylinder rolling or sliding on a wall has been undertaken in two and three dimensions. The cylinder motion is specified from a set of five discrete rotation rates, ranging from prograde through to retrograde rolling. A Reynolds number range of 20-500 is considered. The effects of the nearby wall and the imposed body motion on the wake structure and dominant wake transitions have been determined. Prograde rolling is shown to destabilize the wake flow, while retrograde rotation delays the onset of unsteady flow to Reynolds numbers well above those observed for a cylinder in an unbounded flow. Two-dimensional simulations show the presence of two recirculation zones in the steady wake, the lengths of which increase approximately linearly with the Reynolds number. Values of the lift and drag coefficient are also reported for the steady flow regime. Results from a linear stability analysis show that the wake initially undergoes a regular bifurcation from a steady two-dimensional flow to a steady three-dimensional wake for all rotation rates. The critical Reynolds number Re<sub>c</sub> of transition and the spanwise wavelength of the dominant mode are shown to be highly dependent on, but smoothly varying with, the rotation rate of the cylinder. Varying the rotation from prograde to retrograde rolling acts to increase the value of Re<sub>c</sub> and decrease the preferred wavelength. The structure of the fully evolved wake mode is then established through three-dimensional simulations. In fact it is found that at Reynolds numbers only marginally (∼5 %) above critical, the three-dimensional simulations indicate that the saturated state becomes time dependent, although at least initially, this does not result in a significant change to the mode structure. It is only at higher Reynolds numbers that the wake undergoes a transition to vortex shedding. An analysis of the three-dimensional transition indicates that it is unlikely to be due to a centrifugal instability despite the superficial similarity to the flow over a backward-facing step, for which the transition mechanism has been speculated to be centrifugal. However, the attached elongated recirculation region and distribution of the spanwise perturbation vorticity field, and the similarity of these features with those of the flow through a partially blocked channel, suggest the possibility that the mechanism is elliptic in nature. Some analysis which supports this conjecture is undertaken.</s0></fC01><fC02 i1="01" i2="3"><s0>001B40G32F</s0></fC02><fC03 i1="01" i2="3" l="FRE"><s0>Ecoulement instationnaire</s0><s5>02</s5></fC03><fC03 i1="01" i2="3" l="ENG"><s0>Unsteady flow</s0><s5>02</s5></fC03><fC03 i1="02" i2="3" l="FRE"><s0>Ecoulement tourbillonnaire</s0><s5>03</s5></fC03><fC03 i1="02" i2="3" l="ENG"><s0>Vortex flow</s0><s5>03</s5></fC03><fC03 i1="03" i2="X" l="FRE"><s0>Détachement tourbillonnaire</s0><s5>04</s5></fC03><fC03 i1="03" i2="X" l="ENG"><s0>Vortex shedding</s0><s5>04</s5></fC03><fC03 i1="03" i2="X" l="SPA"><s0>Desprendimiento vorticial</s0><s5>04</s5></fC03><fC03 i1="04" i2="3" l="FRE"><s0>Sillage</s0><s5>08</s5></fC03><fC03 i1="04" i2="3" l="ENG"><s0>Wakes</s0><s5>08</s5></fC03><fC03 i1="05" i2="X" l="FRE"><s0>Cylindre tournant</s0><s5>09</s5></fC03><fC03 i1="05" i2="X" l="ENG"><s0>Rotating cylinder</s0><s5>09</s5></fC03><fC03 i1="05" i2="X" l="SPA"><s0>Cilindro rotativo</s0><s5>09</s5></fC03><fC03 i1="06" i2="3" l="FRE"><s0>Génération maille</s0><s5>12</s5></fC03><fC03 i1="06" i2="3" l="ENG"><s0>Mesh generation</s0><s5>12</s5></fC03><fC03 i1="07" i2="3" l="FRE"><s0>Modélisation</s0><s5>15</s5></fC03><fC03 i1="07" i2="3" l="ENG"><s0>Modelling</s0><s5>15</s5></fC03><fC03 i1="08" i2="3" l="FRE"><s0>Simulation numérique</s0><s5>16</s5></fC03><fC03 i1="08" i2="3" l="ENG"><s0>Digital simulation</s0><s5>16</s5></fC03><fC03 i1="09" i2="3" l="FRE"><s0>Visualisation écoulement</s0><s5>17</s5></fC03><fC03 i1="09" i2="3" l="ENG"><s0>Flow visualization</s0><s5>17</s5></fC03><fC03 i1="10" i2="X" l="FRE"><s0>Contact roulant glissant</s0><s5>29</s5></fC03><fC03 i1="10" i2="X" l="ENG"><s0>Rolling sliding contact</s0><s5>29</s5></fC03><fC03 i1="10" i2="X" l="SPA"><s0>Contacto rodante deslizante</s0><s5>29</s5></fC03><fC03 i1="11" i2="3" l="FRE"><s0>Translation</s0><s5>30</s5></fC03><fC03 i1="11" i2="3" l="ENG"><s0>Translation</s0><s5>30</s5></fC03><fC03 i1="12" i2="3" l="FRE"><s0>Vorticité</s0><s5>31</s5></fC03><fC03 i1="12" i2="3" l="ENG"><s0>Vorticity</s0><s5>31</s5></fC03><fC03 i1="13" i2="X" l="FRE"><s0>Coefficient portance</s0><s5>32</s5></fC03><fC03 i1="13" i2="X" l="ENG"><s0>Lift coefficient</s0><s5>32</s5></fC03><fC03 i1="13" i2="X" l="SPA"><s0>Coeficiente sustentador</s0><s5>32</s5></fC03><fC03 i1="14" i2="3" l="FRE"><s0>4732F</s0><s4>INC</s4><s5>56</s5></fC03><fN21><s1>165</s1></fN21></pA></standard><server><NO>PASCAL 10-0248008 INIST</NO><ET>The wake behind a cylinder rolling on a wall at varying rotation rates</ET><AU>STEWART (B. E.); THOMPSON (M. C.); LEWEKE (T.); HOURIGAN (K.)</AU><AF>Fluids Laboratory for Aeronautical and Industrial Research (FLAIR), Department of Mechanical and Aerospace Engineering, Monash University/Melbourne, Victoria 3800/Australie (1 aut., 2 aut., 4 aut.); Institut de Recherche sur les Phénomènes Hors Equilibre (IRPHE), CNRS/Universités Aix-Marseille, 49 rue Frédéric Joliot-Curie, BP 146/13384 Marseille/France (1 aut., 3 aut.); Division of Biological Engineering, Monash University/Melbourne, Victoria 3800/Australie (4 aut.)</AF><DT>Publication en série; Niveau analytique</DT><SO>Journal of Fluid Mechanics; ISSN 0022-1120; Coden JFLSA7; Royaume-Uni; Da. 2010; Vol. 648; Pp. 225-256; Bibl. 2 p.</SO><LA>Anglais</LA><EA>A study investigating the flow around a cylinder rolling or sliding on a wall has been undertaken in two and three dimensions. The cylinder motion is specified from a set of five discrete rotation rates, ranging from prograde through to retrograde rolling. A Reynolds number range of 20-500 is considered. The effects of the nearby wall and the imposed body motion on the wake structure and dominant wake transitions have been determined. Prograde rolling is shown to destabilize the wake flow, while retrograde rotation delays the onset of unsteady flow to Reynolds numbers well above those observed for a cylinder in an unbounded flow. Two-dimensional simulations show the presence of two recirculation zones in the steady wake, the lengths of which increase approximately linearly with the Reynolds number. Values of the lift and drag coefficient are also reported for the steady flow regime. Results from a linear stability analysis show that the wake initially undergoes a regular bifurcation from a steady two-dimensional flow to a steady three-dimensional wake for all rotation rates. The critical Reynolds number Re<sub>c</sub> of transition and the spanwise wavelength of the dominant mode are shown to be highly dependent on, but smoothly varying with, the rotation rate of the cylinder. Varying the rotation from prograde to retrograde rolling acts to increase the value of Re<sub>c</sub> and decrease the preferred wavelength. The structure of the fully evolved wake mode is then established through three-dimensional simulations. In fact it is found that at Reynolds numbers only marginally (∼5 %) above critical, the three-dimensional simulations indicate that the saturated state becomes time dependent, although at least initially, this does not result in a significant change to the mode structure. It is only at higher Reynolds numbers that the wake undergoes a transition to vortex shedding. An analysis of the three-dimensional transition indicates that it is unlikely to be due to a centrifugal instability despite the superficial similarity to the flow over a backward-facing step, for which the transition mechanism has been speculated to be centrifugal. However, the attached elongated recirculation region and distribution of the spanwise perturbation vorticity field, and the similarity of these features with those of the flow through a partially blocked channel, suggest the possibility that the mechanism is elliptic in nature. Some analysis which supports this conjecture is undertaken.</EA><CC>001B40G32F</CC><FD>Ecoulement instationnaire; Ecoulement tourbillonnaire; Détachement tourbillonnaire; Sillage; Cylindre tournant; Génération maille; Modélisation; Simulation numérique; Visualisation écoulement; Contact roulant glissant; Translation; Vorticité; Coefficient portance; 4732F</FD><ED>Unsteady flow; Vortex flow; Vortex shedding; Wakes; Rotating cylinder; Mesh generation; Modelling; Digital simulation; Flow visualization; Rolling sliding contact; Translation; Vorticity; Lift coefficient</ED><SD>Desprendimiento vorticial; Cilindro rotativo; Contacto rodante deslizante; Coeficiente sustentador</SD><LO>INIST-5180.354000180606410100</LO><ID>10-0248008</ID></server></inist></record>Pour manipuler ce document sous Unix (Dilib)
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|wiki= Wicri/Asie
|area= AustralieFrV1
|flux= PascalFrancis
|étape= Corpus
|type= RBID
|clé= Pascal:10-0248008
|texte= The wake behind a cylinder rolling on a wall at varying rotation rates
}}
| This area was generated with Dilib version V0.6.33. |  |