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Papers by Olof Grundestam
Engineering Turbulence Modelling and Experiments 6, 2005
ABSTRACT
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Springer Proceedings in Physics, 2009
The influence of moderate rotation rate on turbulent channel flow is that the turbulence is suppr... more The influence of moderate rotation rate on turbulent channel flow is that the turbulence is suppressed on the stable side and augmented on the unstable side because of the Coriolis force. With increasing rotation rate the turbulent region becomes restricted to a decreasing zone near the unstable wall. For the rotation number, Ro > 3 (normalized by bulk velocity and
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50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2012
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50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2012
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50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2012
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50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2012
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Acta Mechanica Sinica, 2014
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The least square projection method is used for obtaining optimal EARSMs for different incomplete ... more The least square projection method is used for obtaining optimal EARSMs for different incomplete sets of basis tensors. The possible singular behaviour depending on the choice of the basis tensors ...
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Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
The influence of moderate rotation rate on turbulent channel flow is that the turbulence is suppr... more The influence of moderate rotation rate on turbulent channel flow is that the turbulence is suppressed on the stable side and augmented on the unstable side because of the Coriolis force. When the rotation increases the turbulent region becomes restricted to an increasingly thin zone near the unstable wall. For a rotation rate, Ro>3 (normalized by bulk velocity and channel
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Bookmarks Related papers MentionsView impact
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Physics of Fluids, 2005
Different techniques for deriving explicit algebraic Reynolds stress models (EARSMs) using incomp... more Different techniques for deriving explicit algebraic Reynolds stress models (EARSMs) using incomplete sets of basis tensors are discussed. The first is the Galerkin method which has been used by several authors. The second alternative technique, proposed here, is based on the least-squares method. The idea behind the latter method is to minimize the error induced in the implicit relation, i.e., the algebraic Reynolds stress model (ARSM) equation, due to the use of incomplete sets of basis tensors. It is argued that since the system matrix of the ARSM equation is not symmetric and positive definite, the Galerkin method does not give EARSMs that are optimal in the strict classical sense. The possible singular behavior depending on the choice of the basis tensors has also been investigated. It is demonstrated that many of the EARSMs based on incomplete tensor bases, expressed in general three-dimensional mean flows, have singularity problems in some flows, such as general two-dimension...
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Journal of Fluid Mechanics, 2008
Fully developed rotating turbulent channel flow has been studied, through direct numerical simula... more Fully developed rotating turbulent channel flow has been studied, through direct numerical simulations, for the complete range of rotation numbers for which the flow is turbulent. The present investigation suggests that complete flow laminarization occurs at a rotation number Ro = 2/Ub denotes the system rotation, Ub is the mean bulk velocity and = u/ is the wall-shear velocity and
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Journal of Fluid Mechanics, 2009
New explicit subgrid stress models are proposed involving the strain rate and rotation rate tenso... more New explicit subgrid stress models are proposed involving the strain rate and rotation rate tensor, which can account for rotation in a natural way. The new models are based on the same methodology that leads to the explicit algebraic Reynolds stress model formulation for Reynolds-averaged Navier–Stokes simulations. One dynamic model and one non-dynamic model are proposed. The non-dynamic model represents a computationally efficient subgrid scale (SGS) stress model, whereas the dynamic model is the most accurate. The models are validated through large eddy simulations (LESs) of spanwise and streamwise rotating channel flow and are compared with the standard and dynamic Smagorinsky models. The proposed explicit dependence on the system rotation improves the description of the mean velocity profiles and the turbulent kinetic energy at high rotation rates. Comparison with the dynamic Smagorinsky model shows that not using the eddy-viscosity assumption improves the description of both t...
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Journal of Fluid Mechanics, 2013
Fully developed plane channel flow rotating in the spanwise direction has been studied analytical... more Fully developed plane channel flow rotating in the spanwise direction has been studied analytically and numerically. Linear stability analysis reveals that all cross-flow modes are stable for supercritical rotation numbers, RogtRocRo\gt R{o}_{c} RogtRoc, where RocR{o}_{c} Roc will approach 3 from below for increasing Reynolds number. Plane Tollmien–Schlichting (TS) waves are independent of rotation and always linearly unstable for supercritical Reynolds numbers. Direct numerical simulation (DNS) of the laminarization process reveals that the turbulence is damped when RoRoRo approaches RocR{o}_{c} Roc. Hence, the laminarization is dominated by linear mechanisms. The flow becomes periodic for supercritical Reynolds numbers and rotation rates, i.e. when RogtRocRo\gt R{o}_{c} RogtRoc and RegtRecRe\gt R{e}_{c} RegtRec. At such rotation rates, all oblique (cross-flow) modes are damped and when the disturbance amplitude becomes small enough, the TS modes start to grow exponentially. Secondary instabilities are initially blocked by the...
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International Journal of Heat and Fluid Flow, 2005
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European Journal of Mechanics - B/Fluids, 2008
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European Journal of Mechanics - B/Fluids, 2006
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Engineering Turbulence Modelling and Experiments 6, 2005
ABSTRACT
Bookmarks Related papers MentionsView impact
Springer Proceedings in Physics, 2009
The influence of moderate rotation rate on turbulent channel flow is that the turbulence is suppr... more The influence of moderate rotation rate on turbulent channel flow is that the turbulence is suppressed on the stable side and augmented on the unstable side because of the Coriolis force. With increasing rotation rate the turbulent region becomes restricted to a decreasing zone near the unstable wall. For the rotation number, Ro > 3 (normalized by bulk velocity and
Bookmarks Related papers MentionsView impact
50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2012
Bookmarks Related papers MentionsView impact
50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2012
Bookmarks Related papers MentionsView impact
50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2012
Bookmarks Related papers MentionsView impact
50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2012
Bookmarks Related papers MentionsView impact
Acta Mechanica Sinica, 2014
Bookmarks Related papers MentionsView impact
The least square projection method is used for obtaining optimal EARSMs for different incomplete ... more The least square projection method is used for obtaining optimal EARSMs for different incomplete sets of basis tensors. The possible singular behaviour depending on the choice of the basis tensors ...
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
The influence of moderate rotation rate on turbulent channel flow is that the turbulence is suppr... more The influence of moderate rotation rate on turbulent channel flow is that the turbulence is suppressed on the stable side and augmented on the unstable side because of the Coriolis force. When the rotation increases the turbulent region becomes restricted to an increasingly thin zone near the unstable wall. For a rotation rate, Ro>3 (normalized by bulk velocity and channel
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Physics of Fluids, 2005
Different techniques for deriving explicit algebraic Reynolds stress models (EARSMs) using incomp... more Different techniques for deriving explicit algebraic Reynolds stress models (EARSMs) using incomplete sets of basis tensors are discussed. The first is the Galerkin method which has been used by several authors. The second alternative technique, proposed here, is based on the least-squares method. The idea behind the latter method is to minimize the error induced in the implicit relation, i.e., the algebraic Reynolds stress model (ARSM) equation, due to the use of incomplete sets of basis tensors. It is argued that since the system matrix of the ARSM equation is not symmetric and positive definite, the Galerkin method does not give EARSMs that are optimal in the strict classical sense. The possible singular behavior depending on the choice of the basis tensors has also been investigated. It is demonstrated that many of the EARSMs based on incomplete tensor bases, expressed in general three-dimensional mean flows, have singularity problems in some flows, such as general two-dimension...
Bookmarks Related papers MentionsView impact
Journal of Fluid Mechanics, 2008
Fully developed rotating turbulent channel flow has been studied, through direct numerical simula... more Fully developed rotating turbulent channel flow has been studied, through direct numerical simulations, for the complete range of rotation numbers for which the flow is turbulent. The present investigation suggests that complete flow laminarization occurs at a rotation number Ro = 2/Ub denotes the system rotation, Ub is the mean bulk velocity and = u/ is the wall-shear velocity and
Bookmarks Related papers MentionsView impact
Journal of Fluid Mechanics, 2009
New explicit subgrid stress models are proposed involving the strain rate and rotation rate tenso... more New explicit subgrid stress models are proposed involving the strain rate and rotation rate tensor, which can account for rotation in a natural way. The new models are based on the same methodology that leads to the explicit algebraic Reynolds stress model formulation for Reynolds-averaged Navier–Stokes simulations. One dynamic model and one non-dynamic model are proposed. The non-dynamic model represents a computationally efficient subgrid scale (SGS) stress model, whereas the dynamic model is the most accurate. The models are validated through large eddy simulations (LESs) of spanwise and streamwise rotating channel flow and are compared with the standard and dynamic Smagorinsky models. The proposed explicit dependence on the system rotation improves the description of the mean velocity profiles and the turbulent kinetic energy at high rotation rates. Comparison with the dynamic Smagorinsky model shows that not using the eddy-viscosity assumption improves the description of both t...
Bookmarks Related papers MentionsView impact
Journal of Fluid Mechanics, 2013
Fully developed plane channel flow rotating in the spanwise direction has been studied analytical... more Fully developed plane channel flow rotating in the spanwise direction has been studied analytically and numerically. Linear stability analysis reveals that all cross-flow modes are stable for supercritical rotation numbers, RogtRocRo\gt R{o}_{c} RogtRoc, where RocR{o}_{c} Roc will approach 3 from below for increasing Reynolds number. Plane Tollmien–Schlichting (TS) waves are independent of rotation and always linearly unstable for supercritical Reynolds numbers. Direct numerical simulation (DNS) of the laminarization process reveals that the turbulence is damped when RoRoRo approaches RocR{o}_{c} Roc. Hence, the laminarization is dominated by linear mechanisms. The flow becomes periodic for supercritical Reynolds numbers and rotation rates, i.e. when RogtRocRo\gt R{o}_{c} RogtRoc and RegtRecRe\gt R{e}_{c} RegtRec. At such rotation rates, all oblique (cross-flow) modes are damped and when the disturbance amplitude becomes small enough, the TS modes start to grow exponentially. Secondary instabilities are initially blocked by the...
Bookmarks Related papers MentionsView impact
International Journal of Heat and Fluid Flow, 2005
Bookmarks Related papers MentionsView impact
European Journal of Mechanics - B/Fluids, 2008
Bookmarks Related papers MentionsView impact
European Journal of Mechanics - B/Fluids, 2006
Bookmarks Related papers MentionsView impact