Interfaces and internal layers in a turbulent boundary layer

Eisma, H.E.; Westerweel, J.; Ooms, G.; Elsinga, G.E.

doi:doi:10.1063/1.4919909

Interfaces and internal layers in a turbulent boundary layer

Title

Interfaces and internal layers in a turbulent boundary layer

Author

Eisma, H.E.
Westerweel, J.
Ooms, G.
Elsinga, G.E.

Faculty

Mechanical, Maritime and Materials Engineering

Department

Process and Energy

Date

2015-05-14

Abstract

New experimental research is presented on the characteristics of interfaces and internal shear layers that are present in a turbulent boundary layer (TBL). The turbulent/non-turbulent (T/NT) interface at the outer boundary of the TBL shows the presence of a finite jump in streamwise velocity and is characterised by a thin shear layer. It appears that similar layers of high shear occur also within the TBL which separate regions of almost uniform momentum. It turns out that they exhibit similar characteristics as the external T/NT interface. Furthermore, the spatial growth rate of the TBL, that is derived from theoretical analysis, can be correctly predicted from a momentum balance near the external T/NT interface. Similarly, the entrainment velocities for the average internal layers have been determined. Results indicate that internal layers move slower in the vicinity of the wall, whereas they move faster than the large scale boundary layer growth rate in the outer region of the TBL. It is believed that shear layers bound large scale flow regions of approximately uniform momentum. Hence, the entrainment velocities of these internal layers may be interpreted as growth rates of the large scale motions in a TBL.

Subject

interfacial properties
boundary layer turbulence
interface dynamics
tensor methods
Reynolds stress modeling

To reference this document use:

https://doi.org/10.4233/uuid:b297400b-b742-4c7e-aaa6-a2f1c7652b74

Publisher

American Institute of Physics

ISSN

1070-6631

Source

https://doi.org/10.1063/1.4919909

Source

Physics of Fluids, 27 (5), 2015