46 citations · 47 across the 6 of their papers we have counts for
6 papers
Coherent-structure dynamics in wall turbulence from state-space trajectories
Emma Lenz, Ahmed Elnahhas, H. Jane Bae
We identify dynamical processes in the near-wall region of turbulent wall-bounded flow by representing coherent-structure energy as trajectories in a low-dimensional state space an…
Are the dynamics of wall turbulence in minimal channels and larger domain channels equivalent? A graph-theoretic approach
Ahmed Elnahhas, Emma Lenz, Parviz Moin +2
This work proposes two algorithmic approaches to extract critical dynamical mechanisms in wall-bounded turbulence with minimum human bias. In both approaches, multiple types of coh…
Wall modeled large-eddy simulations of flow over the Sandia Axisymmetric Transonic Bump
Rahul Agrawal, Ahmed Elnahhas, Parviz Moin
Wall-modeled large-eddy simulations (WMLES) are conducted for the flow over the Sandia Axisymmetric Transonic Bump (ATB) at bump chord Reynolds number, Re = 1x10^6 and Mach number,…
On the enhancement of boundary layer skin friction by turbulence: an angular momentum approach
Ahmed Elnahhas, Perry L. Johnson
Turbulence enhances the wall shear stress in boundary layers, significantly increasing the drag on streamlined bodies. Other flow features such as freestream pressure gradients and…
Toward a flow-structure-based wall-modeled large-eddy simulation paradigm
Ahmed Elnahhas, Adrián Lozano-Durán, Parviz Moin
A promising and cost-effective method for numerical simulation of high Re wall-bounded flows is wall-modeled large-eddy simulation. Most wall models are formulated from the Reynold…
On the evolution of the velocity gradient tensor in transitional boundary layers
Ahmed Elnahhas, Perry L. Johnson, Adrián Lozano-Durán +1
We study the transition to turbulence from the perspective of the velocity gradient tensor dynamics. Our work is motivated by the observation of nonlinear structures emerging durin…