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Changes in cardiovascular hemodynamics are closely related to the development of aortic regurgitation, a type of valvular heart disease. Metrics derived from blood flows are used to indicate aortic regurgitation onset and evaluate its…

Computer Vision and Pattern Recognition · Computer Science 2022-04-07 Derek Long , Cameron McMurdo , Edward Ferdian , Charlene A. Mauger , David Marlevi , Alistair A. Young , Martyn P. Nash

Nonlinear waves are studied in a mixture of liquid and gas bubbles. Influence of viscosity and heat transfer is taken into consideration on propagation of the pressure waves. Nonlinear evolution equations of the second and the third order…

Pattern Formation and Solitons · Physics 2011-12-23 Nikolay A. Kudryashov , Dmitry I. Sinelshchikov

The analysis of nonlinear wave equations has experienced a dramatic growth in the last ten years or so. The key factor in this has been the transition from linear analysis, first to the study of bilinear and multilinear wave interactions,…

Analysis of PDEs · Mathematics 2007-05-23 Daniel Tataru

The separation of measured arterial pressure into a reservoir pressure and an excess pressure was introduced nearly 20 years ago as an heuristic hypothesis. We demonstrate that a two-time asymptotic analysis of the 1-D conservation…

Quantitative Methods · Quantitative Biology 2024-04-18 Kim H. Parker , Alun D. Hughes

A nonlinear Schr\"odinger equation with variable coefficients for surface waves on a large-scale steady nonuniform current has been derived without the assumption of a relative smallness of the velocity of the current. This equation can…

Fluid Dynamics · Physics 2017-04-14 V. P. Ruban

Laminar-to-turbulence transition in zero-pressure-gradient boundary layer at Mach 4.5 is studied using direct numerical simulations. For a given level of total disturbance energy, the inflow spectra was designed to correspond to the…

Fluid Dynamics · Physics 2018-12-03 Reza Jahanbakhshi , Tamer A. Zaki

A noteworthy aspect in blood flow modeling is the definition of the mechanical interaction between the fluid flow and the biological structure that contains it, namely the vessel wall. It has been demonstrated that the addition of a viscous…

Fluid Dynamics · Physics 2022-06-14 Francesco Piccioli , Giulia Bertaglia , Alessandro Valiani , Valerio Caleffi

We study propagation of traveling waves in a blood filled elastic artery with an axially symmetric dilatation (an idealized aneurysm) in long-wave approximation.The processes in the injured artery are modelled by equations for the motion of…

Fluid Dynamics · Physics 2017-03-21 E. V. Nikolova , I. P. Jordanov , Z. I. Dimitrova , N. K. Vitanov

Acoustic perturbations in a parallel relativistic flow of an inviscid fluid are considered. The general expression for the frequency of the sound waves in a uniformly (with zero shear) moving medium is derived. It is shown that relativity…

Astrophysics · Physics 2007-05-23 A. D. Rogava , V. I. Berezhiani , S. M. Mahajan

We use a one dimensional symmetric exclusion model to study pressure and osmosis driven flows through molecular-sized channels, such as biological membrane channels and zeolite pores. Analytic expressions are found for the steady-state flow…

Soft Condensed Matter · Physics 2008-02-03 Tom Chou

It is known that a finite-size homogeneous granular fluid develops an hydrodynamic-like instability when dissipation crosses a threshold value. This instability is analyzed in terms of modified hydrodynamic equations: first, a source term…

Statistical Mechanics · Physics 2009-10-31 R. Soto , M. Mareschal , M. Malek Mansour

The 1-D theory of flow in the arteries yields an equation for the wave speed in terms of the density of blood and the distensibility of the vessel. By means of this equation there is a duality between the equation for the wave speed and the…

Fluid Dynamics · Physics 2021-06-21 Kim H. Parker

We develop new variational principles to study stability and equilibrium of axisymmetric flows. We show that there is an infinite number of steady state solutions. We show that these steady states maximize a (non-universal) $H$-function. We…

Fluid Dynamics · Physics 2016-08-16 Nicolas Leprovost , Bérengère Dubrulle , Pierre-Henri Chavanis

This paper studies the stability and large-time behavior of the three-dimensional (3-D) Boltzmann equation near shock profiles. We prove the nonlinear stability of the composite wave consisting of two shock profiles under general…

Analysis of PDEs · Mathematics 2024-02-08 Dingqun Deng , Lingda Xu

Turbulent flows driven by a vertically invariant body force were proven to become exactly two-dimensional above a critical rotation rate, using upper bound theory. This transition in dimensionality of a turbulent flow has key consequences…

Fluid Dynamics · Physics 2023-07-19 Kannabiran Seshasayanan , Basile Gallet

The statistical properties of the phases of several modes nonlinearly coupled in a random system are investigated by means of a Hamiltonian model with disordered couplings. The regime in which the modes have a stationary distribution of…

Statistical Mechanics · Physics 2011-09-14 Claudio Conti , Luca Leuzzi

The evolution of non-adiabatic perturbations in models with multiple coupled perfect fluids with non-adiabatic sound speed is considered. Instead of splitting the entropy perturbation into relative and intrinsic parts, we introduce a set of…

General Relativity and Quantum Cosmology · Physics 2011-05-12 N. A. Koshelev

The observation of fluid-like behavior in nucleus-nucleus, proton-nucleus and high-multiplicity proton-proton collisions motivates systematic studies of how different measurements approach their fluid-dynamic limit. We have developed…

High Energy Physics - Phenomenology · Physics 2020-11-11 Aleksi Kurkela , Seyed Farid Taghavi , Urs Achim Wiedemann , Bin Wu

The aim of this paper is to discuss the appropriate modelling of in- and outflow boundary conditions for nonlinear drift-diffusion models for the transport of particles including size exclusion and their effect on the behaviour of…

Analysis of PDEs · Mathematics 2016-11-03 Martin Burger , Jan-Frederik Pietschmann

Using analytical expressions for the pressure and velocity waveforms in tapered vessels, we construct a linear 1D model for wave propagation in stenotic vessels in the frequency domain. We demonstrate that using only two parameters to…

Fluid Dynamics · Physics 2019-07-24 George Papadakis , Jean Raspaud