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Helmut Ziegfeld Baumert

Helmut Ziegfeld Baumert
IAMARIS GbR - Research and Consulting, Ludwigslust, Germany · Physics

Dr. Dr. Dipl.-Phys.

About

101
Publications
38,726
Reads
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1,078
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Introduction
When I finished my study of physics in Dresden/DDR, I asked myself what, under the given conditions, I could contribute to a better understanding of our environment. Encouraged by a few people I started to study (1) turbulence and (2) phytoplankton photosynthesis, because one half of global carbon fixation is done by marine phytoplankton, and oceans and atmosphere are turbulent as a rule. Both problems were exciting and today I am happy that I could move them a few mm forward.
Additional affiliations
January 2013 - present
IAMARIS GbR - Research and Consulting, Ludwigslust, Germany
Position
  • Geschäftsführer/Managing Director
January 2009 - August 2012
IAMARIS e.V.
Position
  • Geschäftsführer/Managing Director
January 2009 - present
University of Hamburg
Position
  • Research Associate
Education
September 1985 - May 1986
Russian Academy of Sciences, Lavrentev Inst. of Hydrodynamics
Field of study
  • Theoretical and computational hydrodynamics
September 1984 - July 1985
Lomonossov Moscow State University, Physics Faculty
Field of study
  • Nonlinear physics and theoretical ecology
September 1972 - June 1974
Humboldt-Universität zu Berlin
Field of study
  • Biophysics & Plant physiology

Publications

Publications (101)
Article
Full-text available
This paper presents a new theory on the behaviour of shear-thickening (dilatant) fluids under turbulent conditions. The structure of a dilatant colloidal fluid in turbulent motion may be characterized by (at least) four characteristic length scales: (i) the 'statistically largest' turbulent scale, , labeling the begin of the inertial part of the wa...
Conference Paper
Full-text available
The talk covers a qualitatively new turbulence theory resting on early ideas of A. N. Kolmogorov and L. Landau during the Kazan seminars [7]. This theory predicts (e.g.) for infinitely high Reynolcs number von Karman's constant as 1/ √ 2π= 0.399 whereas Prince-ton's superpipe recently reconfirmed the international standard value as 0.40 +/-0.02 [1]...
Technical Report
Full-text available
The Kolmogorov-Baumert theory of turbulence of 2013 (known also as K-Omega closure) is applied to the special case of stably stratified fluids and the experiment of Dickey and Mellor from 1980. The theory predicts the universal constants of turbulence, like the Karman constant (1/SQRT(2 pi) =0.399) and Kolmogorov's spectral constants. The topic is...
Conference Paper
Full-text available
This contribution presents the results of a novel theory of shear-generated turbulence at asymptotically high Reynolds numbers in incompressible fluids (“Eulerian turbulence”). It is free of empirical parameters and based on a two-fluids concept: an ensemble of quasi-rigid dipole-vortex tubes (vortex filaments, excitations) as quasiparticles in cha...
Conference Paper
Full-text available
We present a dynamic model of inland water bodies with varying volume/water level. It is most usefully applied in water-management studies, e.g. of land-use change, eutrophication or hygienic or climate-change issues. Typically we use either long observational data series and/or meso-scale meteorological (e.g. METRAS) and/or hydrological catchment...
Research
Full-text available
This paper presents a new theory of turbulent mixing in stirred reactors. The degree of homogeneity of a mixed fluid may be characterized by Kolmogorov's microscale. The smaller its value, the better homogeneity. It scales inversely with the fourth root of the energy flux applied in the stirring process. This is true for Newtonian fluids. In non-Ne...
Article
Full-text available
This paper presents a new theory of turbulent mixing in stirred reactors. The degree of homogeneity of a mixed fluid may be characterized by the Kolmogorov micro-scale. The smaller its value, the better homogeneity. The micro-scale scales inversely with the fourth root of the energy dissipation rate in the stirring process. The higher this rate, th...
Conference Paper
Full-text available
On water-quality alarm models, with special regard to the model ALAMEK for the Hau and Can Tho River networks (Mekong, SR Vietnam) by Helmut Z. Baumert , Gisbert Stoyan , Heiko Apel , Nguyen Viet Dung Chemical spills in major rivers eventually damage the economy and ecology of large and densely populated regions. They may happen in trans-bounda...
Book
Full-text available
Local explosions, train accidents, huge fires, and/or storms cause chemical spills in major rivers that eventually damage the economy and ecology of large and densely populated regions. This may happen in transboundary rivers and influence foreign relations and international security. Notorious examples are the Sandoz/Basel (CH) accident at Rhine R...
Conference Paper
Full-text available
The talk proposes explanations for substantial and longstanding contradictions between laboratory experiments and field observations. It focuses on the critical Richardson number and applicability limits of local similarity theories for stably stratified flows in atmosphere and oceans, as recently been initiated by a paper of Grachev et al. (BLM 20...
Conference Paper
Full-text available
Hydrological characteristics & model setup Preliminary results Explosions, huge res, and storms often cause chemical spills in major rivers that eventually damage the economy and ecology of large and densely populated regions. Notorious examples are the Sandoz accident at Rhine River (1986) and the Harbin chemical spill at Amur River (2005). This p...
Article
Full-text available
This study starts with balances deduced by Baumert and Peters (2004, 2005) from results of stratified-shear experiments made in channels and wind tunnels by Itsweire (1984) and Rohr and Van Atta (1987), and of free-decay experiments in a resting stratified tank by Dickey and Mellor (1980). Using a modification of Canuto's (2002) ideas on turbulence...
Article
Full-text available
This paper presents a parameter-free theory of shear-generated turbulence at asymptotically high Reynolds numbers in incompressible fluids. It is based on a two-fluids concept. Both components are materially identical and inviscid. The first component is an ensemble of quasi-rigid dipole-vortex tubes as quasi-particles in chaotic motion. The second...
Article
Full-text available
In the spirit of Prandtl's conjecture of 1926, for turbulence at high Reynolds number we present an analogy with the kinetic theory of gases, with dipoles made of quasi-rigid and 'dressed' vortex tubes as frictionless, incompressible but deformable quasi-particles. Their movements are governed by Helmholtz' elementary vortex rules applied locally....
Article
Full-text available
The paper presents a theory of shear-generated turbulence at asymptotically high Reynolds numbers. It is based on an ensemble of dipole vortex tubes taken as quasi-particles and realized in form of rings, hairpins or filament couples of potentially finite length. In a not necesserily planar cross sectional area through a vortex tangle, taken locall...
Article
Full-text available
This paper extends a turbulence closure-like model for stably stratified flows into a new dynamic domain in which turbulence is generated by internal gravity waves rather than mean shear. The model turbulent kinetic energy (TKE, K) balance, its first equation, incorporates a term for the energy transfer from internal waves to turbulence. This energ...
Article
The River Saar is a heavily impounded river with an average discharge of 80 m3 s−1. The German reach of the River Saar, i.e. the lower 90km, was gradually impounded from 1977–2000, resulting in a doubled average water depth (today 4.2m). In parallel to river development, water pollution was decreased strongly, relieving the critical oxygen budget i...
Article
Full-text available
A new two-equation, closure-like turbulence model for stably stratified flows is introduced which uses the turbulent kinetic energy (K) and the turbulent enstrophy (Ω) as primary variables. It accounts for mean shear – and internal wave-driven mixing in the two limits of mean shear and no waves and waves but no mean shear, respectively. The traditi...
Article
The quantitative description of phytoplankton growth, dynamic photoacclimation and photosynthesis in dependence on temperature, irradiance, trace element and nutrient availability is still a matter of debate and competing ideas in the literature, mainly due to a lack of new critical experiments and to non-unique mathematical descriptions. This pape...
Article
Mixing between overflows and ambient water masses is a critical problem of deep-water mass formation in the downwelling branch of the meridional overturning circulation of the ocean. Modeling approaches that have been tested so far rely either on algebraic parameterizations in hydrostatic ocean circulation models, or on large eddy simulations that...
Article
A simple k–ε turbulence closure is introduced which has no stability functions but instead a Richardson number-dependent turbulent Prandtl number. Its free parameters are determined in a comparison with microstructure observations from a stratified and sheared tidal estuary and laboratory measurements. The closure is able to simulate observed turbu...
Article
Mixing of overflows released from polar and marginal seas is a key process shaping the structure of the meridional overturning circulation. Ocean general circulation models have difficulty in resolving the overflows, and therefore they must rely on parameterizations. In this study, the performance of a set of turbulence closures in reproducing mixi...
Poster
Full-text available
Simulations of reservoir ecosystems were carried out by means of the coupled hydrodynamical ecological model SALMO which is vertically resolved. It comprises modules for (i) turbulent diffusion, seiches and the hydrological balance, (ii) advection and sedimentation and (iii) the internal biological/chemical reactions (photosynthesis, grazing, nutri...
Article
Full-text available
Extensive estuarine microstructure and flow/stratification measurements are used as a basis for validating simple, but physically appropriate turbulence closure models of k-arepsilon and k-Ømega form, the latter without free parameters. The difficulties in achieving quantitative, 1:1 model-observation comparisons are discussed. Results indicate tha...
Chapter
Full-text available
Dies ist eine Zusammenfassung der zum Projekt Bedeutung der Stillwasserzonen und des Interstitials für die Nährstoffelimination in der Elbe beigetragenen Ergebnisse. Der Beitrag illustriert die eingesetzten Arbeitsme-thoden und fokussiert auf Hauptergebnisse. Ziel der nachstehend dargestellten Arbeiten war es, Hilfsmittel für die Berücksichtigung v...
Data
Die nachfolgende Zusammenfassung der von HYDROMOD Wissenschaftliche Beratung GbR zum Projekt Bedeutung der Stillwasserzonen und des Interstitials für die Nährstoff-elimination in der Elbe beigetragenen Ergebnisse, die bereits im Detail dargelegt wurden [Baumert et al. 2000, 2001, 2003], illustriert die eingesetzten Arbeitsmethoden und fokussiert au...
Chapter
Full-text available
Die nachfolgende Zusammenfassung der von HYDROMOD Wissenschaftliche Beratung GbR zum Projekt Bedeutung der Stillwasserzonen und des Interstitials für die Nährstoff-elimination in der Elbe beigetragenen Ergebnisse, die bereits im Detail dargelegt wurden [Baumert et al. 2000, 2001, 2003], illustriert die eingesetzten Arbeitsmethoden und fokussiert au...
Article
Full-text available
Das Modell SALMO, die ökologische Komponente des GETAS-Modellsystems, simuliert das Nahrungsnetz der Freiwasserzone stehender Gewässer. Das Gleichungssystem besteht aus gewöhnlichen Differentialgleichungen für die Zustandsgrößen gelöstes Orthophosphat, gelöster anorganischer Stickstoff, Sauerstoff, allochthoner Detritus, Zooplankton und Phytoplankt...
Article
Full-text available
Die Computersimulation ökologisch relevanter hydrophysikalischer Vorgänge und Phänomene in Talsperren wird am erfolgreichen Anwendungsbeispiel der Saidenbachtalsperre (Sachsen) in den Jahren 1995 bis 1997 beschrieben: Thermohaline Schichtung, Scherungs- und konvektive Turbulenz, windgetriebene Strömung, Corioliskraft, Eis- und Schneedecke, kurze in...
Article
Full-text available
In about 45 000 freshwater reservoirs worldwide, physical, chemical and biological processes form complex interaction webs governed by hydrological, meteorological and catchment variables. The acronym GETAS stands for "Coupled hydrodynamico-ecological simulation for the management of reservoirs" - a joint project of German consulting companies unde...
Article
Separate hydrodynamical and ecological modelling approaches already enable the investigation of selected problems of reservoir management. However, the coupled version only allows a combined examination of water quantity and water quality without more or less arbitrary assumptions for the physical boundary conditions (e.g. on the stratification and...
Article
Full-text available
The ecological component of the coupled model is based on a generalized and extended version of the lake model SALMO (Simulation by an Analytical Lake Model). This model describes the pelagic zone of lakes and reservoirs by means of ordinary differential equations for dissolved reactive phosphorus, dissolved inorganic nitrogen, oxygen, external det...
Article
Full-text available
The successful computer simulation of ecologically relevant hydrophysical processes and phenomenae in freshwater reservoirs is described for the upland reservoir Saidenbach (Saxonia), for the years 1995-97: thermo-haline stratification, shear and convection generated turbulence, wind-driven currents, Coriolis force, ice and snow cover, short intern...
Article
Full-text available
A new simple two-equation turbulence closure is constructed by hypothesizing that there is an extra energy sink in the turbulent kinetic energy (k) equation representing the transfer of energy from k to internal waves and other nonturbulent motions. This sink neither contributes to the buoyancy flux nor to dissipation, the nonturbulent mode being t...
Article
The requirements of ‘comprehensive’ or ‘compatible’ observational data sets for developing and verifying models are examined. ‘Compatibility’ over the range of key parameters involves accuracy, spatial and temporal extent, and resolution. The importance of documentation is emphasised on all aspects from experimental strategy to sensor calibration....
Article
Full-text available
For the special hydrodynamic situation of unbounded homogeneous shear layers, turbulence closure models of Mellor-Yamada type (MY) and k-ε type are put into a single canonical form. For this situation we show that conventional versions of MY and various k-ε versions lack a proper steady state, and are unable to simulate the most basic properties of...
Article
Full-text available
Der Aufsatz behandelt Turbulenzschließungen für geschichtete Strömungen unter dem Aspekt turbulenter Längenskalen. Für die kritische Situation einer homogenen Scherschicht werden das Mellor-Yamada (MY) 2+1/2 und das k-eps-Modell in eine kanonische Form gebracht und miteinander verglichen. Es zeigt sich, daß das k-eps-Modell einen freien Parameter...
Article
The role of small-scale processes in models of coastal seas is reviewed, and the respective uses of vertically integrated and vertically resolving models are described. Although applied with heavily tuned empirical parameters to the Holderness coast a vertically integrated model shows the importance of surface waves for predicting suspended particu...
Conference Paper
Full-text available
Der Beitrag behandelt ein dynamisches, geo-referenziertes Animations-, Visualisierungs- und Informationssystem für hydrographische und begleitende Daten am Beispiel des gezeitenbeeinflußten Elbe-Ästuars (MAGIC Elbe PC). Im Beispiel wurden Daten eines dreidimensionalen hydrodynamisch-numerischen Modells verwendet. Sie lagen auf einem weitgehend regu...
Article
Full-text available
By means of a numerical model of an idealized flat-bottom estuary, the paper studies the hydrodynamic control of the turbidity zone by the combined effect of the salt wedge and tidal movements. The model is of two-dimensional (x, z) finite-difference type with high resolution in time and space. It computes momentum, surface elevation, salinity, sus...
Conference Paper
Full-text available
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Article
Assuming constant temperature and light limitation. for reversible photoinhibition and photoadaptation in phytoplankton two new modelling approaches are presented. The first follows an idea of Jones and Kok (1966) and describes photoinhibition as a consequence of the serial structure of the Z-scheme. The second interpretes photoadaptation as a dyna...
Article
Full-text available
This paper investigates the interaction between stratification and turbulence by means of turbulence models. The standard and the advanced turbulent kinetic energy - dissipation (κ-ε) model are derived theoretically, including algebraic stress relations. It is shown that a certain empirical constant in the standard model turns out to be a complicat...
Article
Full-text available
This paper investigates the interaction between turbulence and stratification by means of turbulence models. The standard and the advanced turbulent kinetic energy -- dissipation (k-eps) model are derived theoretically, including algebraic stress relations. It is shown that a certain empirical constant in the standard model turns out to be a compli...
Chapter
This paper aims to give a list of questions that the biogeochemical modelling community will pose for physicists in the context of the design and development of a “Model of Ocean Biogeochemical Processes”. It has no pretensions to being all-encompassing, rather it surveys the physical topics we see as the most relevant to the global ocean flux stud...
Article
Full-text available
For horizontally homogeneous barotropic conditions, nonrotational tidal (M2) cycles of hydrodynamic fields are computed by the standard k-ε turbulence model for large Reynolds numbers. The characteristic tidal time lag between current and turbulent kinetic energy at the flow reversal turned out to be close to measurements in shallow tidal rivers re...
Data
This is an application of the 3D computer model HMT89 for turbulent stratified shear flows with free surface. The southern North Sea is studied in the vicinity of Heligoland island. The currents follow a more or less circular M2 tide. The classical island wake could not be found here due to the rotation of the tidal flow vector. In summer the cold...
Article
Full-text available
This is an application of the 3D computer model HMT89 for turbulent stratified shear flows with free surface. The southern North Sea is studied in the vicinity of Heligoland island. The currents follow a more or less circular M2 tide. The classical island wake could not be found here due to the rotation of the tidal flow vector. In summer the cold...
Article
The paper describes a convection-diffusion model with dead zones for the non-stationary transport of water-soluble toxic materials in rivers. Different numerical schemes for the model equations are analyzed and compared with exact analytical solutions. The different schemes are valuated with special consideration of the practical restrictions of mi...
Article
Full-text available
A hierarchical spatial structure of a research concept is proposed to determine the biospheric controls of the hydrologic cycle through process studies and field experiments for the purpose of developing models of the energy and water fluxes in the soil-vegetation-atmosphere system at temporal and spatial scales ranging from minutes to centuries an...
Article
The described method is based on a) an empirical formula which links the measured subsurface currents of photosynthetically active solar radiation (PSASR) (at 350-700 nm) with the appropriate measured positions of the sun and b) astronomical formulas for the position of the sun relative to the time of the day, the day of the year, and the geographi...
Article
Using the maximum quantum yield of photosynthesis, the maximum daily integral of photosynthetically active radiation (PAR) and the euphotic zone depth as a basis, general formulae for the upper limits to gross and net carbon fixation in natural waters are derived by theoretical considerations. The results are compared with a set of extremely high p...
Chapter
A computer program, allowing the computation of stationary and transient water quality in river networks, and considering different possibly non-linearly interacting water quality components has been developed. The graph of the network is part of the input data. The model of the hydrophysical and ecological problem under consideration is a coupled...
Article
The basic equation of transverse mixing in rivers and streams is given. A simple analytical solution (Gaussian distribution) is derived, firstly, assuming uniform transverse distributions of longitudinal flow velocity, depth, and transverse mixing coefficient. Using a modified linear regression technique, the cross sectional average of the transver...