Hostname: page-component-586b7cd67f-dsjbd Total loading time: 0 Render date: 2024-11-26T22:40:16.170Z Has data issue: false hasContentIssue false

Effects of inertia and stratification in incompressible ideal fluids: pressure imbalances by rigid confinement

Published online by Cambridge University Press:  06 June 2013

R. Camassa
Affiliation:
Carolina Center for Interdisciplinary Applied Mathematics, Department of Mathematics, University of North Carolina, Chapel Hill, NC 27599, USA
S. Chen
Affiliation:
Carolina Center for Interdisciplinary Applied Mathematics, Department of Mathematics, University of North Carolina, Chapel Hill, NC 27599, USA
G. Falqui
Affiliation:
Dipartimento di Matematica e Applicazioni, Università di Milano-Bicocca, Milano, 20125, Italy
G. Ortenzi*
Affiliation:
Dipartimento di Matematica e Applicazioni, Università di Milano-Bicocca, Milano, 20125, Italy
M. Pedroni
Affiliation:
Dipartimento di Ingegneria, Università di Bergamo, Dalmine (BG), 24044, Italy
*
Email address for correspondence: [email protected]

Abstract

Consequences of density stratification are studied for an ideal (Euler) incompressible fluid, confined to move under gravity between rigid lids but otherwise free to move along horizontal directions. Initial conditions that generate horizontal pressure imbalances in a laterally unbounded domain are examined. The aim is to show analytically the existence of classes of initial data for which total horizontal momentum evolves in time, even though only vertical forces act on the fluid in this set-up. A simple class of such initial conditions, leading to momentum evolution, is identified by systematic asymptotic expansions of the governing inhomogeneous Euler equations in the small-density-variation limit. These results for Euler equations are compared and confirmed with long-wave asymptotic models, which can handle arbitrary density variations and provide closed-form mathematical expressions for limiting cases. In particular, the role of wave dispersion arising from the fluid inertia is captured by the long-wave models, even for short-time dynamics emanating from initial conditions outside the models’ asymptotic range of validity. These results are compared with direct numerical simulations for variable-density Euler fluids, which further validate the numerical algorithms and the analysis.

Type
Papers
Copyright
©2013 Cambridge University Press 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Almgren, A. S., Bell, J. B., Colella, P., Howell, L. H. & Welcome, M. L. 1998 A conservative adaptive projection method for the variable density incompressible Navier–Stokes equations. J. Comput. Phys. 142, 146.Google Scholar
Baines, P. G. 1995 Topographic Effects in Stratified Flows. Cambridge University Press.Google Scholar
Benjamin, T. B. 1986 On the Boussinesq model for two-dimensional wave motions in heterogeneous fluids. J. Fluid Mech. 165, 445474.CrossRefGoogle Scholar
Boonkasame, A. & Milewski, P. 2012 The stability of large-amplitude shallow interfacial non-Boussinesq flows. Stud. Appl. Maths 128, 4058.CrossRefGoogle Scholar
Camassa, R., Chen, S., Falqui, G., Ortenzi, G. & Pedroni, M. 2012 An inertia ‘paradox’ for incompressible stratified Euler fluids. J. Fluid Mech. 695, 330–240.Google Scholar
Camassa, R., Choi, W., Michallet, H., Rusås, P.-O. & Sveen, J. K. 2006 On the realm of validity of strongly nonlinear asymptotic approximations for internal waves. J. Fluid Mech. 549, 123.Google Scholar
Camassa, R. & Levermore, C. D. 1997 Layer-mean quantities, local conservation laws, and vorticity. Phys. Rev. Lett. 78, 650653.Google Scholar
Camassa, R. & Tiron, R. 2011 Optimal two-layer approximation for continuous density stratification. J. Fluid Mech. 669, 3254.Google Scholar
Choi, W. & Camassa, R. 1999 Fully nonlinear internal waves in a two-fluid system. J. Fluid Mech. 396, 136.Google Scholar
Esler, J. G. & Pearce, J. D. 2011 Dispersive dam-break and lock-exchange flows in a two-layer fluid. J. Fluid Mech. 667, 555585.Google Scholar
Gelfand, I. M & Shilov, G. E. 1964 Generalized Functions. Academic.Google Scholar
Gradshteyn, I. S, Ryzhik, I. M., Jeffrey, A. & Zwillinger, D. 2000 Tables of Integrals, Series, and Products. Academic.Google Scholar
Milewski, P., Tabak, E., Turner, C., Rosales, R. R. & Mezanque, F. 2004 Nonlinear stability of two-layer flows. Commun. Math. Sci. 2, 427442.Google Scholar
Wu, T. Y. 1981 Long waves in ocean and coastal waters. J. Engng Mech. 107, 501522.Google Scholar
Yih, C. 1980 Stratified Flows. Academic.Google Scholar
Zakharov, V. E. & Kuznetsov, E. A. 1997 Hamiltonian formalism for nonlinear waves. Phys. Usp. 40, 10871116.Google Scholar
Zakharov, V. E., Musher, S. L. & Rubenchik, A. M. 1985 Hamiltonian approach to the description of nonlinear plasma phenomena. Phys. Rep. C, 285366.Google Scholar