Plenary Lecture

The Structure of Stable Stratified Boundary Layers: Study with of Nonlocal Turbulence Model

Albert Kurbatskiy
Institute of Theoretical and Applied Mechanics
Russian Academy of Sciences, Siberian Branch,
Novosibirsk State University
630090, Novosibirsk,
Russia
E-mail: kurbat@nsu.ru
 

Abstract: Two types of vertical turbulence structure have been identified, one the “traditional” boundary layer, in which turbulence is generated at the surface and transported upward, in contrast to the second type, where turbulence is transported downward from a primary source aloft in the boundary layer. The latter has been referred to as an “upside-down boundary layer”. In this case the turbulence may burst downward toward the surface as an event process. In this study, the boundary layer is upside down if turbulence increases with height and the transport of turbulence energy is downward toward the surface. Presumably, a similar structure can be developed in flow of air from warm area (urban heat island, for example) to cool land surfaces, where the horizontal gradient of temperature between air above the city and air above the rural area generates thermal turbulent circulation. If this turbulence generation is substantially larger than the generation of turbulence due to surface processes, then the vertical transport of turbulence is downward toward the surface. In present study the vertical profiles of wind speed, temperature and turbulent quantities in nocturnal urban boundary layer, calculated by means of improved меsoscale model, is analyzed toward the aim of understanding the vertical structure of the nocturnal urban boundary layer. A large set of field and laboratory measurements, and large eddy simulation (LES) data indicates that in stably stratified flows turbulent mixing exists up to Ri ~ O(100), meaning that there is practically no Ri(cr). On the other hand, traditional local turbulence models entail a critical Ri(cr) ~O(1) above which turbulence ceases to exist and are therefore unable to explain the above data. In this study it is shown, that the discussed here the nonlocal turbulence model is capable to reproduce the above data for arbitrary Ri.

Brief Biography of the Speaker:

Field of research: Fluid dynamics, turbulence modeling, numerical simulation, environment flows.

Surname:  Kurbatskiy                         First name:  Albert                               Date of birth: March 9, 1937

Affiliation:             Laboratory of Turbulence Modeling, Institute of Theoretical and Applied Mechanics (ITAM SB RAS) Russian Academy of Science, Siberian Branch and Professor at the Department of Physics, Novosibirsk State University (NSU).

Address:               Institutskaya Street, 4/1, 630090 Novosibirsk, Russia

Phone:  +7(383)3307805 Fax:  +7(383)3307268                        E-mail:  kurbat@nsu.ru

Education:            Graduated from Physics Department of Novosibirsk State University (NSU), 1963.

Brief description of professional career (including the title of the dissertation work, the year and the Institution where it has been defended):

1.   Junior, Senior, Leading Principal Scientific Researcher, Principal Scientific Researcher of ITAM SB RAS, January, 1964 – till now.

2.   Professor at the Department of Physics, Novosibirsk State University (NSU), 1987-till now.

Ph.D. Thesis: "Modeling of turbulent mixing layer with a chemical reaction», 1975, Institute of Thermophysics of Russian Academy of Sciences, Siberian Branch.

Degree of Doctor (Physics and Mathematics): «Mathematical modeling of non-local turbulent transport of the momentum and heat», 1984, Institute of Thermophysics of Russian Academy of Sciences, Siberian Branch.

Other fields:  The membership on the Academic council of the Department of Physics at the NSU, the member of the editorial board of the Thermophysics and Aeromechanics International Journal (Russian Academy of Sciences, Siberian Branch, Novosibirsk).

List of recent grants for fundamental research: Grant INTAS-OPEN-97-2022 (1998-2001, investigator); Grants of Russian Foundation for Basic Research (1997-99, 2000-02, 2003-05, 2006-08; team leader).

Publications:  Number of communications to scientific meetings: 49. Number of papers in refereed journals:  75. Number of all science papers (including reprints):  104.