On the oscillatory modes of compressible thermal convection in inclined differentially heated cavities

Marcello Lappa, Tomislav Gradinscak

Research output: Contribution to journalArticle

  • 2 Citations

Abstract

We consider the case of a tall differentially heated cavity (containing air) for which the buoyancy flow is in the so-called boundary-layer regime (displaying thin regions featured by strong temperature gradients adjacent to the vertical walls and thermally stratified fluid in the centre). By using a numerical method able to account for compressibility and variable viscosity effects, we investigate the response of such a system to the application of temperature differences in a range of characteristic numbers for which the resulting flow is expected to be time-periodic or highly time-dependent. More precisely, the problem is examined by allowing both the Rayleigh number and the inclination (teta) of this configuration with respect to the vertical direction to span relatively wide intervals (1.8x10^5<=Ra<=3x10^6, -90<=teta<=90). Insights into the influence of variable thermodynamic properties are obtained by comparing such numerical results with equivalent simulations based on the classical Boussinesq approximation. The evolution of the considered system towards a fully turbulent state is also discussed to a certain extent.
LanguageEnglish
Pages412-436
Number of pages25
JournalInternational Journal of Heat and Mass Transfer
Volume121
Early online date10 Jan 2018
DOIs
StatePublished - 30 Jun 2018

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Buoyancy
Compressibility
free convection
Thermal gradients
Numerical methods
temperature gradients
Boundary layers
Thermodynamic properties
Viscosity
Boussinesq approximation
cavities
Fluids
Rayleigh number
Air
buoyancy
compressibility
inclination
boundary layers
thermodynamic properties
viscosity

Keywords

  • differentially heated cavity
  • buoyancy flow
  • numerical method
  • compressibility
  • variable viscosity

Cite this

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abstract = "We consider the case of a tall differentially heated cavity (containing air) for which the buoyancy flow is in the so-called boundary-layer regime (displaying thin regions featured by strong temperature gradients adjacent to the vertical walls and thermally stratified fluid in the centre). By using a numerical method able to account for compressibility and variable viscosity effects, we investigate the response of such a system to the application of temperature differences in a range of characteristic numbers for which the resulting flow is expected to be time-periodic or highly time-dependent. More precisely, the problem is examined by allowing both the Rayleigh number and the inclination (teta) of this configuration with respect to the vertical direction to span relatively wide intervals (1.8x10^5<=Ra<=3x10^6, -90<=teta<=90). Insights into the influence of variable thermodynamic properties are obtained by comparing such numerical results with equivalent simulations based on the classical Boussinesq approximation. The evolution of the considered system towards a fully turbulent state is also discussed to a certain extent.",
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On the oscillatory modes of compressible thermal convection in inclined differentially heated cavities. / Lappa, Marcello; Gradinscak, Tomislav.

In: International Journal of Heat and Mass Transfer, Vol. 121, 30.06.2018, p. 412-436.

Research output: Contribution to journalArticle

TY - JOUR

T1 - On the oscillatory modes of compressible thermal convection in inclined differentially heated cavities

AU - Lappa,Marcello

AU - Gradinscak,Tomislav

PY - 2018/6/30

Y1 - 2018/6/30

N2 - We consider the case of a tall differentially heated cavity (containing air) for which the buoyancy flow is in the so-called boundary-layer regime (displaying thin regions featured by strong temperature gradients adjacent to the vertical walls and thermally stratified fluid in the centre). By using a numerical method able to account for compressibility and variable viscosity effects, we investigate the response of such a system to the application of temperature differences in a range of characteristic numbers for which the resulting flow is expected to be time-periodic or highly time-dependent. More precisely, the problem is examined by allowing both the Rayleigh number and the inclination (teta) of this configuration with respect to the vertical direction to span relatively wide intervals (1.8x10^5<=Ra<=3x10^6, -90<=teta<=90). Insights into the influence of variable thermodynamic properties are obtained by comparing such numerical results with equivalent simulations based on the classical Boussinesq approximation. The evolution of the considered system towards a fully turbulent state is also discussed to a certain extent.

AB - We consider the case of a tall differentially heated cavity (containing air) for which the buoyancy flow is in the so-called boundary-layer regime (displaying thin regions featured by strong temperature gradients adjacent to the vertical walls and thermally stratified fluid in the centre). By using a numerical method able to account for compressibility and variable viscosity effects, we investigate the response of such a system to the application of temperature differences in a range of characteristic numbers for which the resulting flow is expected to be time-periodic or highly time-dependent. More precisely, the problem is examined by allowing both the Rayleigh number and the inclination (teta) of this configuration with respect to the vertical direction to span relatively wide intervals (1.8x10^5<=Ra<=3x10^6, -90<=teta<=90). Insights into the influence of variable thermodynamic properties are obtained by comparing such numerical results with equivalent simulations based on the classical Boussinesq approximation. The evolution of the considered system towards a fully turbulent state is also discussed to a certain extent.

KW - differentially heated cavity

KW - buoyancy flow

KW - numerical method

KW - compressibility

KW - variable viscosity

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JO - International Journal of Heat and Mass Transfer

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