Documents disponibles écrits par cet auteur

Heat and fluid flow around a sphere with cylindrical bore / Andreas Richter in Journal of heat transfer, Vol. 134 N° 7 (Juillet 2012) 

Public ISBD [article]  in Journal of heat transfer > Vol. 134 N° 7 (Juillet 2012) . - 13 p. Titre : Heat and fluid flow around a sphere with cylindrical bore Type de document : texte imprimé Auteurs : Andreas Richter, Auteur ; Petr A. Nikrityuk, Auteur Année de publication : 2012 Article en page(s) : 13 p. Note générale : heat transfer Langues : Anglais (eng) Mots-clés : heat  transfer;  drag  coefficient;  Nusselt  number;  spherical  ring;  sphere;  particle Index. décimale : 536 Chaleur. Thermodynamique Résumé : This work is devoted to the numerical investigation of heat and fluid flow past a sphere with a centric, cylindrical bore. Such spherical rings are of interest in many technological processes. In chemical reactors, for example, spherical rings are used as a catalyst with an increased reacting surface. Motivated by this fact, we considered spherical rings with different bores and different orientations in flow regimes corresponding to Reynolds numbers from 10 up to 300. The results show a significant influence of the bore diameter on the symmetry and hence the steadiness of the flow field. The Nusselt number can be increased, which leads to a moderate rise in the drag coefficient. Thereby, the effect of the borehole depends on the Reynolds number, the bore diameter, and the angle of attack. For that reason, drag forces and total heat transfers do not simply follow the heat exchanging surface area. Based on the presented results, new correlations are given for both the drag coefficient and the Nusselt number; correlations which incorporate the bore geometry and the bore orientation in the flow field. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO000134000007 [...] [article] Heat and fluid flow around a sphere with cylindrical bore [texte imprimé] / Andreas Richter, Auteur ; Petr A. Nikrityuk, Auteur . - 2012 . - 13 p. heat transfer Langues : Anglais (eng) in Journal of heat transfer > Vol. 134 N° 7 (Juillet 2012) . - 13 p. Mots-clés : heat  transfer;  drag  coefficient;  Nusselt  number;  spherical  ring;  sphere;  particle Index. décimale : 536 Chaleur. Thermodynamique Résumé : This work is devoted to the numerical investigation of heat and fluid flow past a sphere with a centric, cylindrical bore. Such spherical rings are of interest in many technological processes. In chemical reactors, for example, spherical rings are used as a catalyst with an increased reacting surface. Motivated by this fact, we considered spherical rings with different bores and different orientations in flow regimes corresponding to Reynolds numbers from 10 up to 300. The results show a significant influence of the bore diameter on the symmetry and hence the steadiness of the flow field. The Nusselt number can be increased, which leads to a moderate rise in the drag coefficient. Thereby, the effect of the borehole depends on the Reynolds number, the bore diameter, and the angle of attack. For that reason, drag forces and total heat transfers do not simply follow the heat exchanging surface area. Based on the presented results, new correlations are given for both the drag coefficient and the Nusselt number; correlations which incorporate the bore geometry and the bore orientation in the flow field. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JHTRAO000134000007 [...]

Numerical investigations of the gas flow inside the bassoon / Andreas Richter in Transactions of the ASME . Journal of fluids engineering, Vol. 134 N° 4 (Avril 2012) 

Public ISBD [article]  in Transactions of the ASME . Journal of fluids engineering > Vol. 134 N° 4 (Avril 2012) . - 10 p. Titre : Numerical investigations of the gas flow inside the bassoon Type de document : texte imprimé Auteurs : Andreas Richter, Auteur Année de publication : 2012 Article en page(s) : 10 p. Note générale : fluids engineering Langues : Anglais (eng) Mots-clés : bassoon;  numerical  acoustics;  musical  acoustics;  aeroacoustics;  compressible  Navier-stokes  equations;  compressible  flow;  CFD;  finite  volume  method Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This work is devoted to the numerical investigation of the gas flow inside a bassoon while it is played. The digitized geometry for the simulations is taken from measurements using laser scan techniques in combination with image processing. Pressure time series measured at the bell and reed were used to define adequate boundaries. Additional pressure measurements inside the musical instrument helped to validate the calculations. With this approach, it was possible to model the characteristics of a bassoon which plays the lowest note. The results of the three-dimensional simulations showed that the acoustic velocities and the underlying mean flow exhibit the same order of magnitude. The calculations indicate that the flow in curved sections such as the crook and the 180 deg bend is considerably different from a steady-state flow. For example, in bends the time-averaged flow features chains of small, alternating vortex pairs, and the pressure distribution differs significantly from a plane wave solution. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JFEGA4000134000004 [...] [article] Numerical investigations of the gas flow inside the bassoon [texte imprimé] / Andreas Richter, Auteur . - 2012 . - 10 p. fluids engineering Langues : Anglais (eng) in Transactions of the ASME . Journal of fluids engineering > Vol. 134 N° 4 (Avril 2012) . - 10 p. Mots-clés : bassoon;  numerical  acoustics;  musical  acoustics;  aeroacoustics;  compressible  Navier-stokes  equations;  compressible  flow;  CFD;  finite  volume  method Index. décimale : 620.1 Essais des matériaux. Défauts des matériaux. Protection des matériaux Résumé : This work is devoted to the numerical investigation of the gas flow inside a bassoon while it is played. The digitized geometry for the simulations is taken from measurements using laser scan techniques in combination with image processing. Pressure time series measured at the bell and reed were used to define adequate boundaries. Additional pressure measurements inside the musical instrument helped to validate the calculations. With this approach, it was possible to model the characteristics of a bassoon which plays the lowest note. The results of the three-dimensional simulations showed that the acoustic velocities and the underlying mean flow exhibit the same order of magnitude. The calculations indicate that the flow in curved sections such as the crook and the 180 deg bend is considerably different from a steady-state flow. For example, in bends the time-averaged flow features chains of small, alternating vortex pairs, and the pressure distribution differs significantly from a plane wave solution. DEWEY : 620.1 ISSN : 0098-2202 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JFEGA4000134000004 [...]