Former FLOW postdoc has received Young Researcher Award in Japan

Former FLOW postdoc Assoc. Prof. Takuya Kawata (Shibaura Institute of Technology, Tokyo, Japan) has received the Young Researcher Award from The Japan Society of Fluid Mechanics .    This award is based on Kawata’s work started at KTH Department of Mechanics which partially was published as 

Kawata, T. & Alfredsson, P.H. 2018 Inverse interscale transport of the Reynolds shear stress in plane Couette turbulence. Phys. Rev. Lett. 120, 244501. ( doi.org/10.1103/PhysRevLett.120.244501 )

The motivation text reads:

"Energy transfer between different scale structures embedded in turbulence has been a central issue, particularly in relation to the self-sustaining mechanisms of wall-bounded turbulence. In addressing this problem, the awardee selected rotating Couette flow as the subject of investigation, which enables effective control over the flow state. By performing precise flow measurements using advanced motion image processing techniques, the spatial distributions of Reynolds stress and turbulent energy were quantitatively analyzed, providing the basis for detailed discussions on their transport characteristics.

To achieve this, the awardee proposed an original analytical framework in which the Reynolds stress transport equation is decomposed into contributions from large and small scales. Furthermore, the transport equation for the Reynolds stress spectrum was derived. Through this spectral-scale analysis, it was revealed that turbulent energy is transferred from large scales to small scales, while Reynolds stress is transported in the opposite direction, from small scales to large scales.

In recent years, the validity of these findings has been further corroborated through direct numerical simulations (DNS). These achievements represent a highly original contribution based on a unique perspective, significantly advancing the current understanding of turbulence self-sustaining mechanisms. The results are also of substantial value beyond rotating Couette flow, offering insights applicable to general wall-bounded turbulence.

Moreover, this research is expected to have wide-ranging impacts not only in advancing the fundamental understanding of turbulence mechanisms but also in practical applications such as heat transfer and scalar transport analyses. Based on these outstanding contributions, the awardee is recognized as an exceptionally promising researcher in fluid dynamics and is deemed highly deserving of the Ryumon Award."