Abstract

This paper focuses on the non-incremental solution of transient coupled non-linear models, in particular the one related to the Rayleigh–Bénard flow problem that models natural thermal convection. For this purpose we are applying the so-called Proper Generalized Decomposition that proceeds by performing space-time separated representations of the different unknown fields involved by the flow model. This non-incremental solution strategy allows significant computational time savings and opens new perspectives for introducing some flow and/or fluid parameters as extra-coordinates.

Highlights

  • This paper focuses on the non-incremental solution of transient coupled non-linear models, in particular the one related to the Rayleigh–Bénard flow problem that models natural thermal convection

  • If instead of the separated representation just discussed, one performs a standard incremental solution, P dD models, d = 1, 2, 3, must be solved (P being the number of time steps, i.e. P = tmax/ Dt, where the time step Dt must be chosen for ensuring the stability conditions)

  • We consider the dimensionless form of the Rayleigh–Bénard model: 8 >>>>

Read more

Summary

Introduction

This paper focuses on the non-incremental solution of transient coupled non-linear models, in particular the one related to the Rayleigh–Bénard flow problem that models natural thermal convection. Several systems and industrial processes are based on natural convection, justifying the impressive volume of work devoted to its understanding and efficient solution during more than one century This model, quite simple in appearance, deserves many surprises related to its intricate nature and many issues concerning its numerical solution, mainly in the case of nonNewtonian fluids and/or when the Rayleigh number is large enough to induce the transition to the turbulence. Models coming from the physics of materials and processes are in general non-linear and strongly coupled It was in this scenario that Pierre Ladeveze proposed in the 1980s a new powerful simulation paradigm, the LATIN method [15] that combines two key ingredients: (i) an efficient non-linear treatment and (ii) a space-time separated representation.

The Proper Generalized Decomposition at a glance
Non-incremental solutions of transient models within the PGD framework
Separated representation of the Rayleigh–Bénard model solution
Separated representation of velocity and temperature fields
Linearization
Separated representation based weak form
Fixed point alternated direction linearization
Numerical results
Newtonian fluid
Power-law fluids
Findings
Conclusions

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.