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A simple and popular Bridgman's model predicts a linear correlation between the thermal conductivity coefficient and the sound velocity of dense liquids. A proportionality coefficient proposed originally is fixed and independent of the…

Soft Condensed Matter · Physics 2023-05-29 Sergey Khrapak

Motivated by the dynamics of micro-scale oscillators with thermo-optical feedback, a simplified third order model, capturing the key features of these oscillators is developed, where each oscillator consists of a displacement variable…

Chaotic Dynamics · Physics 2022-04-26 Richard H. Rand , Alan T. Zehnder , B. Shayak , Aditya Bhaskar

It is demonstrated that the general theory of Casimir and van der Waals forces describes the interaction-induced equilibrium thermodynamic potentials of the damped harmonic oscillator bilinearly coupled to the environment. An extended model…

Statistical Mechanics · Physics 2021-06-01 Yu. S. Barash

Following the analytic approach to thermodynamics developed by Stueckelberg, we study the evolution equations of a closed thermodynamic system consisting of point particles in a fluid. We obtain a system of coupled differential equations…

Fluid Dynamics · Physics 2011-02-17 C. Gruber , S. D. Brechet

In this paper an asymptotic homogenization method for the analysis of composite materials with periodic microstructure in presence of thermodiffusion is described. Appropriate down-scaling relations correlating the microscopic fields to the…

Mathematical Physics · Physics 2015-12-31 A. Bacigalupo , L. Morini , A. Piccolroaz

The paper is devoted to an adjoint complement to the universal Law of the Wall (LoW) for fluid dynamic momentum boundary layers. The latter typically follows from a strongly simplified, unidirectional shear flow under a constant stress…

Fluid Dynamics · Physics 2020-12-18 Niklas Kühl , Peter M. Müller , Thomas Rung

The use of adjoint solvers is considered in order to obtain the sensitivity of clinical measures in aneurysms to incomplete (or unknown) boundary conditions and/or geometry. It is shown that these techniques offer interesting theoretical…

Medical Physics · Physics 2023-01-13 Rainald Löhner , Harbir Antil , Juan Cebral , Fernando Mut

In this work, we aim to establish a detailed description of the physical mechanisms of intrinsic thermoacoustic modes and their interplay with duct acoustic modes. The biglobal linear stability analysis of an anchored laminar flame in an…

Fluid Dynamics · Physics 2024-09-26 Lu Chen , Yu Lv

This work deals with a number of questions relative to the discrete and continuous adjoint fields associated with the compressible Euler equations and classical aerodynamic functions. The consistency of the discrete adjoint equations with…

Computational Physics · Physics 2021-11-17 Jacques Peter , Florent Renac , Clément Labbé

For systems in equilibrium at a temperature $T$, thermal noise and energy damping are related to $T$ through the fluctuation-dissipation theorem (FDT). We study here an extension of the FDT to an out of equilibrium steady state: a…

Statistical Mechanics · Physics 2023-03-23 Alex Fontana , Ludovic Bellon

In recent years, the use of adjoint vectors in Computational Fluid Dynamics (CFD) has seen a dramatic rise. Their utility in numerous applications, including design optimization, data assimilation, and mesh adaptation has sparked the…

Computational Engineering, Finance, and Science · Computer Science 2017-12-05 Steven M. Kast

The present study makes use of the adjoint modes of the Linearized Reactive Flow (LRF) equations to investigate the Intrinsic Thermoacoustic (ITA) feedback loop of a laminar premixed slit flame. The analysis shows that the ITA feedback loop…

Fluid Dynamics · Physics 2023-07-25 Grégoire Varillon , Philipp Brokof , Wolfgang Polifke

Thermoacoustic instabilities in gas turbines and aeroengine combustors falls within the category of complex systems. They can be described phenomenologically using nonlinear stochastic differential equations, which constitute the grounds…

Fluid Dynamics · Physics 2016-12-09 Edouard Boujo , Alexey Denisov , Bruno Schuermans , Nicolas Noiray

In this article we extend the results presented in Ref. [Phys. Rev. A 76, 032101 (2007)] to treat quantitatively the effects of reservoirs at finite temperature in a bosonic dissipative network: a chain of coupled harmonic oscillators…

Quantum Physics · Physics 2015-05-13 M. A. de Ponte , S. S. Mizrahi , M. H. Y. Moussa

Nonlinear dynamics have long been exploited in order to damp vibrations in solid mechanics. The phenomenon of irreversible energy transfer from a linear primary system to a nonlinear absorber has driven great attention to the optimal design…

We present an adjoint sensitivity method for hybrid discrete -- continuous systems, extending previously published forward sensitivity methods. We treat ordinary differential equations and differential-algebraic equations of index up to two…

Optimization and Control · Mathematics 2019-04-19 Radu Serban , Antonio Recuero

Fluctuations in conjugate thermodynamic variables are studied using the cross-correlation function. A new procedure is given enabling the derivation of fluctuation formulas for a system in equilibrium. Specifically, the cross-correlation…

Statistical Mechanics · Physics 2024-07-03 Jean-Luc Garden

Linear dielectric thermodynamics are formally developed to explore the isothermal and adiabatic temperature - pressure dependence of dielectric constants. The refractive index of optical materials is widely measured in the literature: it is…

Materials Science · Physics 2023-11-15 S. J. Burns

The work is inspired by thermo-and photoacoustic imaging, where recent efforts are devoted to take into account attenuation and varying wave speed parameters. In this paper we derive and analyze causal equations describing propagation of…

Mathematical Physics · Physics 2011-12-06 Kowar Richard , Scherzer Otmar , Bonnefond Xavier

This work presents an illustrative application of the Second-Order Adjoint Sensitivity Analysis Methodology (2nd-ASAM) developed by Cacuci (2015) to a paradigm nonlinear heat conduction benchmark, which models a conceptual experimental test…

Optimization and Control · Mathematics 2016-01-29 Dan Gabriel Cacuci