Direct Numerical Simulation of a Turbulent Channel Flow with Forchheimer Drag

Bhattacharjee, S and Mortikov, E and Debolskiy, A and Kadantsev, E and Pandit, R and Vesala, T and Sahoo, G (2022) Direct Numerical Simulation of a Turbulent Channel Flow with Forchheimer Drag. In: Boundary-Layer Meteorology .

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Abstract

We characterize the turbulent flow, using direct numerical simulations (DNS), within a closed channel between two parallel walls with a canopy of constant areal density profile on the lower wall. The canopy is modelled using different formulations of the Forchheimer drag, and the characteristic properties of the turbulent flows are compared. In particular, we examine the influence of the added drag on the mean profiles of the flow and the balance equations of the turbulent kinetic energy. We find that the different formulations of the drag strongly affect the mean and the turbulent profiles close to the canopy. We also observe the changes in the local anisotropy of the turbulent flow in the presence of the canopy. We find that there is an equal transfer of energy from the streamwise component to both the transverse components outside the canopy by the pressure and velocity-gradient correlation; inside the canopy, this correlation removes energy from both the streamwise and the wall-normal fluctuations and injects into the spanwise component. As a result, the energy content of the spanwise fluctuations is comparable to that of the streamwise components inside the canopy. Inside the canopy, we observe that the turbulent transport of Reynolds stresses acts as an important source of turbulent kinetic energy. The pressure-fluctuation transport plays a significant role inside the canopy close to the wall and is comparable to turbulent transport. © 2022, The Author(s), under exclusive licence to Springer Nature B.V.

Item Type:	Journal Article
Publication:	Boundary-Layer Meteorology
Publisher:	Springer Science and Business Media B.V.
Additional Information:	The copyright for this article belongs to Springer Science and Business Media B.V.
Keywords:	Atmospheric thermodynamics; Boundary layer flow; Boundary layers; Channel flow; Drag; Energy transfer; Kinetic energy; Kinetics; Numerical models; Reynolds number; Turbulence; Turbulent flow, Areal densities; Boundary layer turbulence; Canopy turbulence; Density profile; Direct-numerical-simulation; Energy; Forchheimer drag; Turbulent channel flows; Turbulent kinetic energy; Turbulent transports, Direct numerical simulation
Department/Centre:	Division of Physical & Mathematical Sciences > Physics
Date Deposited:	08 Oct 2022 05:01
Last Modified:	08 Oct 2022 05:01
URI:	https://eprints.iisc.ac.in/id/eprint/77320

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