Publications by Peter Monkewitz

On the difficulty of determining Kármán "constants" from direct numerical simulations

The difficulty of determining the slope of the famed logarithmic law in the mean velocity profile of wall-bounded turbulent flows, the inverse of the K & aacute;rm & aacute;n "constant" kappa, from direct numerical simulations (DNS) is discussed for channe ...

Melville2024

The hunt for the Karman 'constant' revisited

Peter Monkewitz

The log law of the wall, joining the inner, near-wall mean velocity profile (MVP) in wall-bounded turbulent flows to the outer region, has been a permanent fixture of turbulence research for over hundred years, but there is still no general agreement on th ...

Cambridge University Press2023

The late start of the mean velocity overlap log law at y(+) = O(10(3)) - a generic feature of turbulent wall layers in ducts

Peter Monkewitz

One of the key observations in the Princeton Superpipe was the late start of the logarithmic mean velocity overlap layer at a wall distance of the order of 10(3) inner units. Between y(+) approximate to 150, the start of the overlap layer in zero pressure ...

Cambridge University Press2021

Asymptotics of streamwise Reynolds stress in wall turbulence

Peter Monkewitz

The scaling of different features of streamwise normal stress profiles uu (+) (y(+)) in turbulent wall-bounded flows is the subject of a long-running debate. Particular points of contention are the scaling of the 'inner' and 'outer' peaks of < uu >(+) at y ...

Cambridge University Press2021

Uncertainty Analysis of the Von Karman Constant for the Mean Centerline Velocity in CICLoPE

Peter Monkewitz

Further examination of the pressure measurement uncertainties in determining the pressure gradient along the fully-developed section of CICLoPE, yields a Karman constant based on the centerline velocity of kappa(CL) = 0.43 +/- 0.06. More significantly, we ...

SPRINGER INTERNATIONAL PUBLISHING AG2019

Revisiting the quest for a universal log-law and the role of pressure gradient in "canonical" wall-bounded turbulent flows

Peter Monkewitz

The trinity of so-called "canonical" wall-bounded turbulent flows, comprising the zero pressure gradient turbulent boundary layer, abbreviated ZPG TBL, turbulent pipe flow, and channel/duct flows has continued to receive intense attention as new and more r ...

Amer Physical Soc2017

Katabatic Flow: A Closed-Form Solution with Spatially-Varying Eddy Diffusivities

Peter Monkewitz, Jiannong Fang, Marc Parlange, Marco Giovanni Giometto

The Nieuwstadt closed-form solution for the stationary Ekman layer is generalized for katabatic flows within the conceptual framework of the Prandtl model. The proposed solution is valid for spatially-varying eddy viscosity and diffusivity (O'Brien type) a ...

Springer Verlag2017

Large-Reynolds-number asymptotics of the streamwise normal stress in zero-pressure-gradient turbulent boundary layers

Peter Monkewitz

A more poetic long title could be 'A voyage from the shifting grounds of existing data on zero-pressure-gradient (abbreviated ZPG) turbulent boundary layers (abbreviated TBLs) to infinite Reynolds number'. Aided by the requirement of consistency with the R ...

Cambridge University Press2015

Systematic errors of skin-friction measurements by oil-film interferometry

Peter Monkewitz, Jean-Daniel Rüedi

In recent years, the independent measurement of wall shear stress with oil-film or oil-drop interferometry has become a cornerstone of turbulent-boundary-layer research as many arguments depend critically on a precise knowledge of the skin friction tau(w)* ...

Cambridge University Press2015

Experimental realization and characterization of unstretched planar one-dimensional diffusion flames

Peter Monkewitz, Etienne Robert

A burner configuration that allows the creation of nearly unstretched one-dimensional diffusion flames has recently been introduced. This paper presents the first detailed characterization of flames produced in such a burner to assess how well they approac ...

Elsevier Science Inc2013

Grid turbulence in dilute polymer solutions: PEO in water

Peter Monkewitz, Richard Vonlanthen

Grid turbulence of polyethylene oxide (PEO) solutions (Polyox WSR-301 in H2O) has been investigated experimentally for three concentrations of 25, 50 and 100 weight ppm, at a turbulence Reynolds number based on a Taylor microscale of Re-lambda approximate ...

Cambridge University Press2013

Thermal-diffusive instabilities in unstretched, planar diffusion flames

Peter Monkewitz, Etienne Robert

The recent development of a novel research burner at EPFL has opened the way for experimental investigations of essentially unstretched planar diffusion flames. In particular, it has become feasible to experimentally validate theoretical models for thermal ...

Elsevier2012

A novel tethered-sphere add-on to enhance grid turbulence

Peter Monkewitz, Richard Vonlanthen

The new turbulence generator consists of a standard uniform grid with tethered spheres attached to its nodes and is capable of producing approximately twice the turbulence energy per unit pressure drop coefficient C (p) than the same bare grid without the ...

Springer-Verlag2011

Wall-bounded turbulent flows at high Reynolds numbers: Recent advances and key issues

Peter Monkewitz

Wall-bounded turbulent flows at high Reynolds numbers have become an increasingly active area of research in recent years. Many challenges remain in theory, scaling, physical understanding, experimental techniques, and numerical simulations. In this paper ...

2010

Correcting hot-wire measurements of stream-wise turbulence intensity in boundary layers

Peter Monkewitz

The current experimental activity aimed at resolving the scaling of stream-wise turbulence intensity profiles (uu) over bar (+)(y(+)) with Reynolds number in turbulent flat plate boundary layers has brought the largely unresolved issue of correcting system ...

2010

CICLoPE-a response to the need for high Reynolds number experiments

Peter Monkewitz

Although the equations governing turbulent flow of fluids are well known, understanding the overwhelming richness of flow phenomena, especially in high Reynolds number turbulent flows, remains one of the grand challenges in physics and engineering. High Re ...

2009

Experimental investigation into localized instabilities of mixed Rayleigh-Benard-Poiseuille convection

Peter Monkewitz, Emeric Grandjean

The stability of the Rayleigh-Benard-Poiseuille flow in a channel with large transverse aspect ratio (ratio of width to vertical channel height) is studied experimentally. The onset of thermal convection in the form of 'transverse rolls' (rolls with axes p ...

Cambridge University Press2009

Experiments in a novel quasi-1D diffusion flame with variable bulk flow

Peter Monkewitz, Etienne Robert

The novel species injector of a recently developed research burner, consisting of an array of hypodermic needles, which allows to produce quasi one-dimensional unstrained diffusion flames has been improved. It is used in a new symmetric design with fuel an ...

2009

New opportunities for detailed flow measurements at high reynolds numbers

Peter Monkewitz

High Reynolds number turbulence is ubiquitous in many flows of practical interest and its understanding is crucial to draw conclusions on the physics of turbulence. Although recent laboratory experiments, measurements in the planetary boundary layer and di ...

Begell House Inc.2009

Criteria for assessing experiments in zero pressure gradient boundary layers

Peter Monkewitz

An extensive set of experimental data, for zero pressure gradient boundary layers, over a wide range of Reynolds number is re-evaluated with the help of a composite profile fitted to the mean-velocity data. Boundary layer parameters such as Pi, H and the t ...

2009