Oscillatory thermocapillary flows in simulated floating zones with time-dependent boundary conditions

R. Montia, R. Savinoa, M. Lappa

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

This study deals with numerical simulations of the Maxus sounding rocket experiment on oscillatory Marangoni convection in liquid bridges. The problem is investigated through direct numerical solution of the non-linear, time-dependent, three-dimensional Navier-Stokes equations. In particular a liquid bridge of silicon oil 2[cs] with a lenght L = 20 [mm] and a diameter D = 20 [mm] is considered. A temperature difference DT= 30 [K] is imposed between the supporting disks, by heating the top disk and cooling the bottom one with different rates of ramping. The results show that the oscillatory flow starts as an "axially running wave" but after a transient time the instability is described by the dynamic model of a "standing wave", with an azimuthal spatial distribution corresponding to m=1 (where m is the critical wave number). After the transition, the disturbances become larger and the azimuthal velocity plays a more important role and the oscillatory field is characterized by a travelling wave. The characteristic times for the onset of the different flow regimes are computed for different rates of ramping.
LanguageEnglish
Pages863-875
Number of pages13
JournalActa Astronautica
Volume41
Issue number12
DOIs
Publication statusPublished - 31 Dec 1997

Fingerprint

Boundary conditions
Sounding rockets
Liquids
Spatial distribution
Navier Stokes equations
Dynamic models
Cooling
Heating
Silicon
Computer simulation
Experiments
Temperature
Oils
Convection

Keywords

  • Navier-Stokes equations
  • Maxus sounding rocket experiment
  • liquid bridges

Cite this

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title = "Oscillatory thermocapillary flows in simulated floating zones with time-dependent boundary conditions",
abstract = "This study deals with numerical simulations of the Maxus sounding rocket experiment on oscillatory Marangoni convection in liquid bridges. The problem is investigated through direct numerical solution of the non-linear, time-dependent, three-dimensional Navier-Stokes equations. In particular a liquid bridge of silicon oil 2[cs] with a lenght L = 20 [mm] and a diameter D = 20 [mm] is considered. A temperature difference DT= 30 [K] is imposed between the supporting disks, by heating the top disk and cooling the bottom one with different rates of ramping. The results show that the oscillatory flow starts as an {"}axially running wave{"} but after a transient time the instability is described by the dynamic model of a {"}standing wave{"}, with an azimuthal spatial distribution corresponding to m=1 (where m is the critical wave number). After the transition, the disturbances become larger and the azimuthal velocity plays a more important role and the oscillatory field is characterized by a travelling wave. The characteristic times for the onset of the different flow regimes are computed for different rates of ramping.",
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Oscillatory thermocapillary flows in simulated floating zones with time-dependent boundary conditions. / Montia, R.; Savinoa, R.; Lappa, M.

In: Acta Astronautica, Vol. 41, No. 12, 31.12.1997, p. 863-875.

Research output: Contribution to journalArticle

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T1 - Oscillatory thermocapillary flows in simulated floating zones with time-dependent boundary conditions

AU - Montia, R.

AU - Savinoa, R.

AU - Lappa, M.

PY - 1997/12/31

Y1 - 1997/12/31

N2 - This study deals with numerical simulations of the Maxus sounding rocket experiment on oscillatory Marangoni convection in liquid bridges. The problem is investigated through direct numerical solution of the non-linear, time-dependent, three-dimensional Navier-Stokes equations. In particular a liquid bridge of silicon oil 2[cs] with a lenght L = 20 [mm] and a diameter D = 20 [mm] is considered. A temperature difference DT= 30 [K] is imposed between the supporting disks, by heating the top disk and cooling the bottom one with different rates of ramping. The results show that the oscillatory flow starts as an "axially running wave" but after a transient time the instability is described by the dynamic model of a "standing wave", with an azimuthal spatial distribution corresponding to m=1 (where m is the critical wave number). After the transition, the disturbances become larger and the azimuthal velocity plays a more important role and the oscillatory field is characterized by a travelling wave. The characteristic times for the onset of the different flow regimes are computed for different rates of ramping.

AB - This study deals with numerical simulations of the Maxus sounding rocket experiment on oscillatory Marangoni convection in liquid bridges. The problem is investigated through direct numerical solution of the non-linear, time-dependent, three-dimensional Navier-Stokes equations. In particular a liquid bridge of silicon oil 2[cs] with a lenght L = 20 [mm] and a diameter D = 20 [mm] is considered. A temperature difference DT= 30 [K] is imposed between the supporting disks, by heating the top disk and cooling the bottom one with different rates of ramping. The results show that the oscillatory flow starts as an "axially running wave" but after a transient time the instability is described by the dynamic model of a "standing wave", with an azimuthal spatial distribution corresponding to m=1 (where m is the critical wave number). After the transition, the disturbances become larger and the azimuthal velocity plays a more important role and the oscillatory field is characterized by a travelling wave. The characteristic times for the onset of the different flow regimes are computed for different rates of ramping.

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