Henk Tennekes

Bio: Henk Tennekes is an academic researcher from Massachusetts Institute of Technology. The author has contributed to research in topics: Turbulence & K-epsilon turbulence model. The author has an hindex of 9, co-authored 11 publications receiving 14934 citations.

A First Course in Turbulence

Abstract: Keywords: turbulence ; transport ; contraintes ; transport ; couche : limite ; ecoulement ; tourbillon ; energie Reference Record created on 2005-11-18, modified on 2016-08-08

Turbulent Transport of Momentum and Heat

Abstract: This chapter contains sections titled: The Reynolds equations, Elements of the kinetic theory of gases, Estimates of the Reynolds stress, Turbulent heat transfer, Turbulent shear flow near a rigid wall

The Statistical Description of Turbulence

Abstract: This chapter contains sections titled: The probability density, Fourier transforms and characteristic functions, Joint statistics and statistical independence, Correlation functions and spectra, The central limit theorem

The simple science of flight : from insects to jumbo jets

Abstract: From the smallest gnat to the largest aircraft, all things that fly obey the same aerodynamic principles "The Simple Science of Flight" offers an introduction to the mechanics of flight and, beyond that, to the scientific attitude that finds wonder in simple calculations, forging connections between, say, the energy efficiency of a peanut butter sandwich and that of the kerosene that fuels a jumbo jet The hero of the book is the Boeing 747, which Tennekes sees as the current pinnacle of human ingenuity in mastering the science of flight Also covered are paper airplanes, kites, gliders, and human-powered flying machines as well as birds and insects Tennekes explains difficult concepts like lift, drag, wing loading and cruising speed through many fascinating comparisons, anecdotes and examples Equations are integrated into the flow of the text Tennekes begins with a simple comparison of the relative fuel consumption of hummingbirds cars, and airplanes, then turns to the relations between an airplane weight, its wing area and its cruising speed, showing that it is possible to collect all flying creatures and flying machines in a single flight diagram He looks at energetics through the considerable efforts of a little 35-gram bird in a wind tunnel There are stories on the effects of headwinds, tailwinds, and other weather conditions that both birds and planes face, on the elegance of the mechanics that makes flight possible, and on the aerodynamics of sophisticated flying toys Tennekes concludes by comparing the Boeing 747 and the supersonic Concorde, with the former emerging as the perfect airplane for intercontinental flights: "just below the speed of sound and just above the weather"

Turbulence in the ocean

Abstract: I. Theory of Turbulence in Stratified Flows.- 1. Definition of Turbulence.- 2. Equations of Turbulent Flow.- 3. Mechanisms of Turbulence Generation in the Ocean.- 3.1 Instability of Vertical Velocity Gradients in Drifting Flow.- 3.2 Overturning of Surface Waves.- 3.3 Instability of Vertical Velocity Gradients in Stratified Large-Scale Oceanic Flows.- 3.4 Hydrodynamic Instability of Quasi-Horizontal Meso-Scale Non-Stationary Flows.- 3.5 Instability of Local Velocity Gradients in Internal Waves.- 3.6 Convection in Layers with Unstable Density Stratification.- 3.7 Instability of Vertical Velocity Gradients in a Bottom Boundary Layer (BBL).- 4. Stratification Effects.- 5. Theory of Turbulence Spectra.- 6. The Small-Scale Structure of Turbulence.- II. Small-Scale Turbulence.- 7. Instruments for The Measurement of Small-Scale Turbulence.- 7.1 Experimental Techniques.- 8. Statistical Characteristics of Turbulence.- 9. Velocity Fluctuations.- 9.1 Root-Mean-Square Values.- 9.2 Correlation Functions and Spectra.- 9.3 Dependence on Local Background Conditions.- 9.4 Spectra of Fluctuation Intensity and Energy Dissipation.- 9.5 Turbulent Energy Dissipation Rate.- 9.6 Climatology of Small-Scale Turbulence.- 10. Temperature Fluctuations.- 10.1 An Indirect Method of Estimating Temperature Fluctuations.- 10.2 Local Temperature Gradients in the Ocean.- 10.3 Variations in Fine-Structure Temperature Profiles.- 10.4 Direct Measurements of High-Frequency Temperature Fluctuations.- 10.5 Turbulent Heat Fluxes.- 10.6 Spectra of High-Frequency Temperature Fluctuations.- 10.7 Spectral Characteristics of the Temperature Variability in the Ocean.- 10.8 Dissipation Rate of Temperature Inhomogeneities.- 11. Fluctuations of Electrical Conductivity and Salinity.- 11.1 Fundamentals.- 11.2 Local Gradients of C and S.- 11.3 Spectral Characteristics.- 11.4 Dependence on Local Background Conditions.- 11.5 Intermittency of Electrical Conductivity Fluctuations.- 11.6 Deep-Sea Measurement Data.- 11.7 Determination of Salinity Fluctuations.- 11.8 Density Fluctuations and Turbulent Mass Flux.- 11.9 Climatology of Electrical Conductivity Fluctuations.- III. Large-Scale Horizontal Turbulence.- 12. Large-Scale Turbulence and Negative Eddy Viscosity.- 13. Theory of Two-Dimensional Turbulence.- 14. Horizontal Turbulence Spectra.- Notes.- References.- Name Index.

Development of a turbulence closure model for geophysical fluid problems

Abstract: Applications of second-moment turbulent closure hypotheses to geophysical fluid problems have developed rapidly since 1973, when genuine predictive skill in coping with the effects of stratification was demonstrated. The purpose here is to synthesize and organize material that has appeared in a number of articles and add new useful material so that a complete (and improved) description of a turbulence model from conception to application is condensed in a single article. It is hoped that this will be a useful reference to users of the model for application to either atmospheric or oceanic boundary layers.

On the identification of a vortex

Abstract: Considerable confusion surrounds the longstanding question of what constitutes a vortex, especially in a turbulent flow. This question, frequently misunderstood as academic, has recently acquired particular significance since coherent structures (CS) in turbulent flows are now commonly regarded as vortices. An objective definition of a vortex should permit the use of vortex dynamics concepts to educe CS, to explain formation and evolutionary dynamics of CS, to explore the role of CS in turbulence phenomena, and to develop viable turbulence models and control strategies for turbulence phenomena. We propose a definition of a vortex in an incompressible flow in terms of the eigenvalues of the symmetric tensor ${\bm {\cal S}}^2 + {\bm \Omega}^2$ are respectively the symmetric and antisymmetric parts of the velocity gradient tensor ${\bm \Delta}{\bm u}$. This definition captures the pressure minimum in a plane perpendicular to the vortex axis at high Reynolds numbers, and also accurately defines vortex cores at low Reynolds numbers, unlike a pressure-minimum criterion. We compare our definition with prior schemes/definitions using exact and numerical solutions of the Euler and Navier–Stokes equations for a variety of laminar and turbulent flows. In contrast to definitions based on the positive second invariant of ${\bm \Delta}{\bm u}$ or the complex eigenvalues of ${\bm \Delta}{\bm u}$, our definition accurately identifies the vortex core in flows where the vortex geometry is intuitively clear.

The Problem of Pattern and Scale in Ecology: The Robert H. MacArthur Award Lecture

Abstract: This book is the second of two volumes in a series on terrestrial and marine comparisons, focusing on the temporal complement of the earlier spatial analysis of patchiness and pattern (Levin et al. 1993). The issue of the relationships among pattern, scale, and patchiness has been framed forcefully in John Steele’s writings of two decades (e.g., Steele 1978). There is no pattern without an observational frame. In the words of Nietzsche, “There are no facts… only interpretations.”

Bubbles, Drops, and Particles

Abstract: The standard κ-ϵ equations and other turbulence models are evaluated with respect to their applicability in swirling, recirculating flows. The turbulence models are formulated on the basis of two separate viewpoints. The first perspective assumes that an isotropic eddy viscosity and the modified Boussinesq hypothesis adequately describe the stress distributions, and that the source of predictive error is a consequence of the modeled terms in the κ-ϵ equations. Both stabilizing and destabilizing Richardson number corrections are incorporated to investigate this line of reasoning. A second viewpoint proposes that the eddy viscosity approach is inherently inadequate and that a redistribution of the stress magnitudes is necessary. Investigation of higher-order closure is pursued on the level of an algebraic stress closure. Various turbulence model predictions are compared with experimental data from a variety of isothermal, confined studies. Supportive swirl comparisons are also performed for a laminar flow case, as well as reacting flow cases. Parallel predictions or contributions from other sources are also consulted where appropriate. Predictive accuracy was found to be a partial function of inlet boundary conditions and numerical diffusion. Despite prediction sensitivity to inlet conditions and numerics, the data comparisons delineate the relative advantages and disadvantages of the various modifications. Possible research avenues in the area of computational modeling of strongly swirling, recirculating flows are reviewed and discussed.