Refine
Year of publication
Document Type
- Article (19)
- Working Paper (11)
- Book (9)
- Part of a Book (3)
- Conference Proceeding (3)
- Preprint (3)
- Lecture (1)
- Other (1)
Keywords
- Bewusstsein (10)
- consciousness (8)
- science (7)
- Religion (6)
- Eriugena (5)
- Evolution (5)
- pattern formation (5)
- religion (5)
- Heisenberg (4)
- Neurobiologie (4)
- Wissenschaft (4)
- decodability (4)
- Apokatastasis (3)
- Cusanus (3)
- Gehirn (3)
- Gemeinsinn (3)
- Homo sapiens (3)
- Kindi (3)
- Lebenskunst (3)
- TMV (3)
- Wissenschaftskommunikation (3)
- Wissenschaftspolitik (3)
- autocatalysis (3)
- brain (3)
- evolution (3)
- human (3)
- wissenschaftliche Politikberatung (3)
- China (2)
- Dekodierung (2)
- Empathie (2)
- Feigl (2)
- Galilei (2)
- Goedel (2)
- Gödel (2)
- Hypatia (2)
- Isaac Israeli (2)
- Kognition (2)
- Kosmologie (2)
- Naturwissenschaften (2)
- RNA (2)
- Trembley (2)
- Willensfreiheit (2)
- Wissenschaftsgeschichte (2)
- anthropic principle (2)
- brain mind (2)
- cognition (2)
- electricity (2)
- empathy (2)
- history (2)
- infectivity (2)
- lateral inhibition (2)
- protein synthesis (2)
- transcendence (2)
- Archäologie (1)
- Assabyah (1)
- Augustin (1)
- Begrenzte Rationalität (1)
- Berlin-Adlershof (1)
- Biowissenschaften (1)
- Boussinesq conditions (1)
- Buoyancy driven flows (1)
- Carnap (1)
- Caspar Friedrich Wolff (1)
- DNA (1)
- Determination (1)
- Elektrizität (1)
- Entscheidungstheorie (1)
- Erkenntnistheorie (1)
- Europe (1)
- Flüssigkeitsreibung (1)
- Fokker-Planck (1)
- Gehirn-Geist-Beziehung (1)
- Geist (1)
- Heraclit (1)
- History of Science (1)
- Hydra (1)
- Internationale Kooperation (1)
- Jesuits (1)
- John Donne (1)
- Kepler (1)
- Keramik (1)
- Khaldun (1)
- Kooperation (1)
- Kulturen (1)
- Kurt Gödel (1)
- Lateral inhibition (1)
- Laterale Inhibition (1)
- Mensch (1)
- Menschwerdung (1)
- Mikroreibung (1)
- Mikroviskosität (1)
- Mind (1)
- Mittelalter (1)
- Molekül (1)
- Molekülrotation (1)
- Moralismus (1)
- Naturwissenschaft und Mathematik (1)
- Neuplatonismus (1)
- Neuroscience (1)
- Nusselt number measurements (1)
- Open Access (1)
- Pattern formation (1)
- Philosophie (1)
- Philosophy of Science (1)
- Polyribosomes (1)
- Polysomes (1)
- Psychological Concepts (1)
- Psychological Instruments (1)
- Psychology (1)
- Publikations- und Kommunikationstechniken (1)
- Pyrometrie (1)
- Regeneration (1)
- Reticulocytes (1)
- Rudolf Carnap (1)
- Schelling (1)
- Selbstbezug (1)
- Selbstrepresentation (1)
- Sozialgeschichte (1)
- Soziobiologie (1)
- Staat (1)
- Staat / Entstehung (1)
- Stokes (1)
- Stokes-Gleichung (1)
- Strategisches Denken (1)
- Strukturbildung (1)
- Taylor Couette flow (1)
- Technische Innovation (1)
- Theory (1)
- Thermal convection (1)
- Thierry (1)
- Unentscheidbarkeit (1)
- Verhalten (1)
- Vertrauen (1)
- Viskosität (1)
- Wiedervereinigung (1)
- Wissenschaftskooperation (1)
- Wolff (1)
- altruism (1)
- axonal branching (1)
- axons (1)
- bounded rationality (1)
- brain evolution (1)
- brain mind relation (1)
- cell aggregates (1)
- combinatorial (1)
- consciouness (1)
- cooperation (1)
- cosmology (1)
- cruciform DNA (1)
- cultural diversity (1)
- cultural pluralism (1)
- decidability (1)
- decision (1)
- decision theory (1)
- desamination (1)
- development (1)
- developmental-biology (1)
- early career (1)
- embryology (1)
- energy dissipation (1)
- finitistic (1)
- finitistisch (1)
- free-will (1)
- gene regulation (1)
- gradients (1)
- growth cone (1)
- guidance (1)
- head formation (1)
- heat (1)
- heat current (1)
- high Rayleigh number convection (1)
- history of science (1)
- history of technology (1)
- holistic (1)
- human capital (1)
- human cognition (1)
- hydra (1)
- hydra regeneration (1)
- income distribution (1)
- international cooperation (1)
- lateral-inhibition (1)
- medieval philosophy (1)
- messenger RNA (1)
- microfriction (1)
- microviscosity (1)
- mind (1)
- molecular biology (1)
- momentum flux (1)
- mutagenesis (1)
- mutation in vitro (1)
- neurobiology (1)
- neurogenesis (1)
- non-Oberbeck-Boussinesq conditions (1)
- open access (1)
- palindromes (1)
- pattern-formation (1)
- philosophy of science (1)
- pipe flow (1)
- polarity (1)
- projection (1)
- promotion of young scientists (1)
- quantum physics (1)
- reaction-diffusion (1)
- regeneration (1)
- retinotectal (1)
- ribonucleic acid (1)
- rotation (1)
- science cooperation (1)
- self refence (1)
- self reference (1)
- self-understanding (1)
- single strand (1)
- sociobiology (1)
- solidarity (1)
- sorting out (1)
- steamships (1)
- techniques of publishing and communication (1)
- terminal arbour (1)
- theology (1)
- theoretica concepts (1)
- thermal convection (1)
- tissue evagination (1)
- translation (1)
- undecidability (1)
- virus (1)
- Ägypten (1)
- Ägypten (Altertum) (1)
Has Fulltext
- yes (50)
Institute
- Veröffentlichungen von Akademiemitgliedern (50) (remove)
Non-Oberbeck-Boussinesq (NOB) effects on the Nusselt number Nu and Reynolds number Re in strongly turbulent Rayleigh-Benard convection in liquids were investigated both experimentally and theoretically. In the experiment, the heat current, the temperature difference, and the temperature at the horizontal mid-plane were measured. Three cells of different heights L, all filled with water and all with aspect ratio T close to 1 were used. For each L, about 1.5 decades in Ra were covered, together spanning the ränge 108 < Ra < 1011. For the largest temperature difference between the bottom and top plates of ? = 40K the kinematic viscosity and the thermal expansion coefficient, due to their temperature dependence, varied by more than a factor of two. The Oberbeck-Boussinesq (OB) approximation of temperature independent material parameters thus was no longer valid. The ratio Ï? of the temperature drops across the bottom and top thermal boundary layers became as small as Ï? = 0.83, as compared to the ratio Ï? = 1 in the OB case. Nevertheless, the Nusselt number Nu was found to be only slightly smaller (at most 1.4%) than in the next larger cell with the same Rayleigh number, where the material parameters were still nearly height-independent. The Reynolds numbers in the OB and NOB case agreed with each other within the experimental resolution of about 2%, showing that NOB effects for this parameter were small as well. Thus Nu and Re are rather insensitive against even significant deviations from OB conditions. Theoretically, we first account for the robustness of Nu with respect to NOB corrections: the NOB effects in the top boundary layer cancel those which arise in the bottom boundary layer as long as they are linear in the temperature difference ?. The net effects on Nu are proportional to ?2 and thus increase only slowly and still remain minor despite drastic material parameter changes. We then extend the Prandtl-Blasius boundary-layer theory to NOB Rayleigh-Benard flow with temperature dependent viscosity and thermal diffusivity. This allows the calculation of the shift of the bulk temperature, the temperature drops across the boundary layers, and the ratio Ï? without introducing any fitting parameter. The calculated quantities are in very good agreement with experiment. When in addition we use the experimental finding that for water the sum of the top and bottom thermal boundary-layer widths (based on the slopes of the temperature profiles at the plates) remains unchanged under NOB effects within experimental resolution, the theory also gives the measured small Nusseltnumber reduction for the NOB case. In addition, it predicts an increase by about 0.5% of the Reynolds number, which is also consistent with the experimental data. By theoretically studying hypothetical liquids with only one of the material parameters being temperature dependent, we shed further light on the origin of NOB corrections in water: While the NOB deviation of x from its OB value Ï? = 1 mainly originates from the temperature dependence of the viscosity, the NOB correction of the Nusselt number primarily originates from the temperature dependence of the thermal diffusivity. Finally, we give the predictions from our theory for the NOB corrections if glycerol is used as operating liquid.