Near-wall turbulence & porous walls | Index |

This part contains documents related to my work on near-wall turbulence, its structure(s) and possible control, initiated during the years 1998-1999 while being at Universidad Politécnica de Madrid under supervision of Javier Jimenez.

- "The instability of streaks in near-wall turbulence". This CTR Research Brief from 1998 (pp. 155-170) by G. Kawahara, J. Jiménez, M. Uhlmann and A. Pinelli describes a simple linear model for the initial phase of streak break-up.
- "Fully developed laminar flow in a plane channel with constant cross flow". Simple analytical expression for the variation of the friction coefficient as a function of blowing/suction is derived here.
- "Estimation of the Persistence of the Effect of a Porous Surface on the Adjacent Turbulent Flow". We describe the transient after an initially porous wall in plane channel flow is suddenly made impermeable in this compressed postscript document.
- "A modified plane channel code for flow with a spatially varying pressure gradient". In this report we (A. Pinelli & M. Uhlmann) describe how a streamwise variation of the mean pressure can be simulated in the setting of a "classical" spectral code [16].
- "Plane channel flow simulation over porous walls" by J. Jiménez, A. Pinelli, M. Uhlmann (Technical Note ETSIA MF-9809, U. Politecnica Madrid) as of 1998. This document describes the numerical method, physical parameters and results of our simulation of flow over Darcy-porous boundaries in detail. Contained is the write-up of our new Fourier/B-spline method.
- "Linear stability analysis of turbulent channel flow including porous walls" by J. Jiménez, G. Kawahara, A. Pinelli, M. Uhlmann (Technical Note ETSIA MF-9811, U. Politecnica Madrid) as of 1998. The report contains an account of the numerical method - based upon a B-spline Galerkin approach - and the results of our stability analysis of a simple model for buffer-layer streaks in plane channel flow. This complementary report documents the way by which turbulent background fluctuations are incorporated, similar as proposed in [17].
- Animated visualizations of coherent structures in turbulent
channel flow over a porous wall are available in MPEG format (in
arguably low quality).
- Title of the movie.
- The geometry used in the simulations.
- Streaks & wall-transpiration.
- Streaks & rollers on the porous wall.
- Streaks & rollers on the impermeable wall.

- "The Influence Of Wall-Porosity Upon The Near-Wall Turbulence Dynamics" by M. Uhlmann, A. Pinelli, J. Jiménez and G. Kawahara (Proc. 8th ETC, Barcelona, 2000, pp. 463-466). This conference contribution sums up our findings regarding the flow over porous walls. There is even a snapshot from the conference reception.
- "Turbulent shear flow over active and passive porous
surfaces" by J. Jiménez, M. Uhlmann, A. Pinelli and G. Kawahara
has appeared in
*J. Fluid Mech.*, 442:89-117, 2001.

markus.uhlmann AT kit.edu

Near-wall turbulence & porous walls | Contents | Index |