123 citations · 700 across the 31 of their papers we have counts for
32 papers
Statistical State Dynamics Eigenmodes and Equilibria support Couette Turbulence
Brian F. Farrell, Petros J. Ioannou
Wide-channel Couette (WCC) turbulence consists primarily of quasi-steady roll-streak structures (RSS) maintained by a self-sustaining process (SSP), yet the Navier-Stokes equations…
Statistical state dynamics modes and equilibria underlie the structure and mechanism of wide channel Couette turbulence
Brian F. Farrell, Petros J. Ioannou
Wide channel Couette (WCC) turbulence is striking in being dominated by a large-scale spanwise periodic structure composed of streamwise streaks and associated roll superstructures…
Statistical state dynamics-based study of the stability of the mean statistical state of wall-bounded turbulence
Brian F. Farrell, Petros J. Ioannou
Turbulence in wall-bounded flows is characterized by stable statistics. Although, in many turbulent systems, this stable statistical state corresponds to a stable fixed point of an…
Investigating nonlinearity in wall turbulence: regenerative versus parametric mechanisms
B. F. Farrell, E. Kim, H. J. Bae +2
Both linear growth processes associated with non-normality of the mean flow and nonlinear interaction transferring energy among fluctuations contribute to maintaining turbulence. H…
Mechanism of Roll-Streak Structure Formation and Maintenance in Turbulent Shear Flow
B. F. Farrell, P. J. Ioannou, M. -A. Nikolaidis
In wall-bounded shear flow the primary coherent structure is the streamwise roll and streak (R-S). Absent of an associated instability the R-S has been ascribed to non-normality me…
POD-based study of turbulent plane Poiseuille flow: comparing structure and dynamics between quasi-linear simulations and DNS
Marios-Andreas Nikolaidis, Petros J. Ioannou, Brian F. Farrell +1
Turbulence in the restricted nonlinear (RNL) dynamics is analyzed and compared with DNS of Poiseuille turbulence at . The structures are obtained by POD analysis of the two…
Synchronization of Low Reynolds Number Plane Couette Turbulence
Marios-Andreas Nikolaidis, Petros J. Ioannou
We demonstrate that a separation of the velocity field in large and small scales according to a streamwise Fourier decomposition identifies subspaces with stable Lyapunov exponents…
Parametric mechanism maintaining Couette flow turbulence verified in DNS implies novel control strategies
Brian F. Farrell, Petros J. Ioannou, Marios-Andreas Nikolaidis
The no-slip boundary condition results in a velocity shear forming in fluid flow near a solid surface. This shear flow supports the turbulence characteristic of fluid flow near bou…
Statistical State Dynamics Based Study of the Role of Nonlinearity in the Maintenance of Turbulence in Couette Flow
Brian F. Farrell, Petros J. Ioannou, Marios-Andreas Nikolaidis
While linear non-normality underlies the mechanism of energy transfer from the externally driven flow to the perturbation field that sustains turbulence, nonlinearity is also known…
The mechanism by which nonlinearity sustains turbulence in plane Couette flow
Marios-Andreas Nikolaidis, Brian F. Farrell, Petros J. Ioannou
Turbulence in wall-bounded shear flow results from a synergistic interaction between linear non-normality and nonlinearity in which non-normal growth of a subset of perturbations c…
Is spontaneous generation of coherent baroclinic flows possible?
Nikolaos A. Bakas, Petros J. Ioannou
Geophysical turbulence is observed to self-organize into large-scale flows such as zonal jets and coherent vortices. Previous studies on barotropic beta-plane turbulence have shown…
Statistical state dynamics of weak jets in barotropic beta-plane turbulence
Nikolaos A. Bakas, Navid C. Constantinou, Petros J. Ioannou
Zonal jets in a barotropic setup emerge out of homogeneous turbulence through a flow-forming instability of the homogeneous turbulent state (`zonostrophic instability') which occur…
A statistical state dynamics approach to wall-turbulence
Brian F. Farrell, Dennice F. Gayme, Petros J. Ioannou
This paper reviews results from the study of wall-bounded turbulent flows using statistical state dynamics (SSD) that demonstrate the benefits of adopting this perspective for unde…
Statistical state dynamics based theory for the formation and equilibration of Saturn's north polar jet
Brian F. Farrell, Petros J. Ioannou
Coherent jets with most of the kinetic energy of the flow are common in atmospheric turbulence. In the gaseous planets these jets are maintained by incoherent turbulence excited by…
Statistical state dynamics-based analysis of the physical mechanisms sustaining and regulating turbulence in Couette flow
Brian F. Farrell, Petros J. Ioannou
This paper describes a study of the self-sustaining process in wall-turbulence based on a second order statistical state dynamics (SSD) model of Couette flow. SSD models with this…
Instability of the roll/streak structure induced by free-stream turbulence in pre-transitional Couette flow
Brian F. Farrell, Petros J. Ioannou, Marios-Andreas Nikolaidis
Although the roll/streak structure is ubiquitous in pre-transitional wall-bounded shear flow, this structure is linearly stable if the idealization of laminar flow is made. Lacking…
A statistical state dynamics-based study of the structure and mechanism of large-scale motions in plane Poiseuille flow
Brian F. Farrell, Petros J. Ioannou, Javier Jiménez +3
The perspective of statistical state dynamics (SSD) has recently been applied to the study of mechanisms underlying turbulence in various physical systems. An example implementatio…
Statistical state dynamics of jet/wave coexistence in barotropic beta-plane turbulence
Navid C. Constantinou, Brian F. Farrell, Petros J. Ioannou
Jets coexist with planetary scale waves in the turbulence of planetary atmospheres. The coherent component of these structures arises from cooperative interaction between the coher…
Emergence of non-zonal coherent structures
Nikolaos A. Bakas, Petros J. Ioannou
Planetary turbulence is observed to self-organize into large-scale structures such as zonal jets and coherent vortices. One of the simplest models that retains the relevant dynamic…
A minimal model of self-sustaining turbulence
Vaughan Thomas, Brian F. Farrell, Petros J. Ioannou +1
In this work we examine the turbulence maintained in a Restricted Nonlinear (RNL) model of plane Couette flow. This model is a computationally efficient approximation of the second…
Statistical State Dynamics: a new perspective on turbulence in shear flow
Brian F. Farrell, Petros J. Ioannou
Traditionally, single realizations of the turbulent state have been the object of study in shear flow turbulence. When a statistical quantity was needed it was obtained from a spat…
A study of decays to strange final states with GlueX in Hall D using components of the BaBar DIRC
The GlueX Collaboration, M. Dugger, B. Ritchie +103
We propose to enhance the kaon identification capabilities of the GlueX detector by constructing an FDIRC (Focusing Detection of Internally Reflected Cherenkov) detector utilizing…
S3T stability of the homogeneous state of barotropic beta-plane turbulence
Nikolaos A. Bakas, Navid C. Constantinou, Petros J. Ioannou
Zonal jets and non-zonal large-scale flows are often present in forced-dissipative barotropic turbulence on a beta-plane. The dynamics underlying the formation of both zonal and no…
Self-sustaining turbulence in a restricted nonlinear model of plane Couette flow
Vaughan L. Thomas, Binh K. Lieu, Mihailo R. Jovanović +3
This paper demonstrates the maintenance of self-sustaining turbulence in a restricted nonlinear (RNL) model of plane Couette flow. The RNL system is derived directly from the Navie…