Department of Geophysics, Faculty of Science, University of Zagreb


On 06 June 2018 at 13:15 h will be held at the Department of Geophysics:
(hall P2) following talk:
Branko Grisogono

(University of Zagreb, Croatia)
 

(In)compatibility between HOST and MOST for stably stratified surface layer

We invite students, graduates and all interested parties to attend the lecture, which will be held in the hall P2, Department of Geophysics, Faculty of Science, University of Zagreb, Horvatovac 95, Zagreb.

An extended expression from Monin-Obukhov Similarity Theory (MOST) is compared with an observed HOckey-Stick Transition (HOST) between near-neutral and stably stratified surface layer (SSL). The results indicate that the extended expression cannot capture the observed characteristics of the relationship between friction velocity and wind speed. After evidencing apparent incompatibility between the approaches, a drag-coefficient perspective (supposed to be generally closer to MOST, yet not opposing HOST a priori), is adapted and extended somewhat. In this way, a new result is obtained where the drag coefficient method produces a ski-like behavior, which is a crucial HOST feature in a qualitative sense. Moreover, a threshold mean wind speed for sustainable continuous turbulence in the SSL is estimated in terms of two drag coefficients and a minimum friction velocity.

 

Author: Maja Telišman-Prtenjak
News list

 ------------------------------------------------------------------------------------------------------


Archive