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Wind tunnels and linearized turbulence and boundary-layer models have been so far necessary to simulate and approximate the stationery lift and drag forces on (base-mounted) airfoils by means of statistically determined or approximated…

Fluid Dynamics · Physics 2025-07-01 Rensley A. Meulens

The air flows in the proximal and distal portions of the human lungs are interconnected: the lower Reynolds number in the deeper generations causes a progressive flow regularization, while mass conservation requires flow rate oscillations…

Fluid Dynamics · Physics 2025-06-18 Marco Atzori , Emanuele Gallorini , Ciro Cottini , Andrea Benassi , Maurizio Quadrio

Energy distributions of high frequency linear wave fields are often modelled in terms of flow or transport equations with ray dynamics given by a Hamiltonian vector field in phase space. Applications arise in underwater and room acoustics,…

Computational Physics · Physics 2014-08-12 David Chappell , Gregor Tanner , Niels Sondergaard , Dominik Loechel

This study is concerned with the statistics of vertical turbulent channel flow laden with inertial particles for two different volume concentrations ($\Phi_{V} = 3 \times 10^{-6}$ and $\Phi_{V} = 5 \times 10^{-5}$) at a Stokes number of…

Fluid Dynamics · Physics 2019-04-22 Guiquan Wang , Kee Onn Fong , Filippo Coletti , Jesse Capecelatro

In order to generalize the well-known spanwise-oscillating-wall technique for drag reduction, non-sinusoidal oscillations of a solid wall are considered as a means to alter the skin-friction drag in a turbulent channel flow. A series of…

Viscous dissipation causes significant energy losses in fluid flows; in ducts, laminar flows provide the minimum resistance to the motion, whereas turbulent currents substantially increase the friction at the wall and the energy requirement…

Fluid Dynamics · Physics 2023-01-25 Giulio Foggi Rota , Alessandro Monti , Marco E. Rosti , Maurizio Quadrio

We determine both the in-plane and out-of-plane dynamics of viscoelastic membranes separating two viscous fluids in order to understand microrheological studies of such membranes. We demonstrate the general viscoelastic signatures in the…

Soft Condensed Matter · Physics 2009-11-07 Alex J. Levine , F. C. MacKintosh

A Lie-group based similarity theory is developed for both momentum and energy distributions in a turbulent pipe flow, leading to asymptotic logarithmic profiles of mean velocity and turbulent kinetic energy. Both channel and pipe data over…

Fluid Dynamics · Physics 2016-06-03 Xi Chen , Fazle Hussain , Zhen-Su She

Analytical/quasi-analytical solutions are proposed for a steady, compressible, two-phase flow in mechanical equilibrium in a rectilinear duct subjected to heating followed by cooling. The flow is driven by the pressure ratio between a…

Fluid Dynamics · Physics 2024-04-17 Solène Schropff , Fabien Petitpas , Eric Daniel

This paper studies a scalable control method for multi-zone heating, ventilation and air-conditioning (HVAC) systems to optimize the energy cost for maintaining thermal comfort and indoor air quality (IAQ) (represented by CO2)…

Systems and Control · Electrical Eng. & Systems 2021-01-05 Yu Yang , Seshadhri Srinivasan , Guoqiang Hu , Costas J. Spanos

The presence of stratified layer in atmosphere and ocean leads to buoyant vertical motions, commonly referred to as plumes. It is important to study the mixing dynamics of a plume at a local scale in order to model their evolution and…

Fluid Dynamics · Physics 2016-11-04 Harish N Mirajkar , Sridhar Balasubramanian

Airflow through the nasal cavity exhibits a wide variety of fluid dynamicsbehaviour due to the intricacy of the nasal geometry. The flow is naturallyunsteady and perhaps turbulent, despite CFD in the literature that assumesa steady laminar…

In this paper, we develop a pulsatile compartmental model of the Fontan circulation and use it to explore the effects of a fenestration added to this physiology. A fenestration is a shunt between the systemic and pulmonary veins that is…

Tissues and Organs · Quantitative Biology 2022-06-23 Zan Ahmad , Lynn H. Jin , Daniel J. Penny , Craig G. Rusin , Charles S. Peskin , Charles Puelz

In this work we present a mathematical framework that quantifies the gas-exchange processes in the lung. The theory is based on the solution of the one-dimensional diffusion equation on a simplified model of lung septum. Gases dissolved…

Quantitative Methods · Quantitative Biology 2010-08-25 Yulin V. Chang

We present a stream-tube model of oxygen exchange inside a human placenta functional unit (a placentone). The effect of villi density on oxygen transfer efficiency is assessed by numerically solving the diffusion-convection equation in a…

Quantitative Methods · Quantitative Biology 2015-01-05 A. S. Serov , C. Salafia , P. Brownbill , D. S. Grebenkov , M. Filoche

We study acoustic propagation in one dimensional water ducts containing many air-filled blocks. The acoustic band structures for the periodic arrangements of the blocks is calculated, whereas the transmission for various random…

Condensed Matter · Physics 2015-06-24 Pi-Gang Luan , Zhen Ye

We revisited the analytical solutions for the tidal circulation in an idealized, frictional, elongated, rotating, and enclosed basin. The parameters in the tidal model with a single vertical layer and two vertical layers, including the…

Atmospheric and Oceanic Physics · Physics 2019-01-30 Sang In Won , Jinseong Kwon , Sung Yong Kim

Accurate simulations of the flow in the human airway are essential for advancing diagnostic methods. Many existing computational studies rely on simplified geometries or turbulence models, limiting their simulation's ability to resolve flow…

We investigate the unsteady lift response of compliant membrane wings in hovering kinematics by combining analytical inviscid theory with experimental results. An unsteady aerodynamic model is derived for a compliant thin aerofoil immersed…

Fluid Dynamics · Physics 2026-01-14 Sonya Tiomkin , Alexander Gehrke

We study analytically and numerically the winding of directed polymers of length $t$ around each other or around a rod. Unconfined polymers in pure media have exponentially decaying winding angle distributions, the decay constant depending…

Statistical Mechanics · Physics 2008-02-03 Barbara Drossel , Mehran Kardar