國立高雄大學圖資館 |

Language: English

Back

Lattice Boltzmann studies of turbule...

Karpikov, Alexander.

Lattice Boltzmann studies of turbulence in non-Newtonian fluids.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Lattice Boltzmann studies of turbulence in non-Newtonian fluids.
Author:	Karpikov, Alexander.
Description:	146 p.
Notes:	Directors: K. R. Sreenivasan; S. A. Orszag.
Notes:	Source: Dissertation Abstracts International, Volume: 66-11, Section: B, page: 6043.
Contained By:	Dissertation Abstracts International66-11B.
Subject:	Physics, Fluid and Plasma.
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3194667
ISBN:	9780542394324

Lattice Boltzmann studies of turbulence in non-Newtonian fluids.
Karpikov, Alexander.

Lattice Boltzmann studies of turbulence in non-Newtonian fluids. - 146 p.

Directors: K. R. Sreenivasan; S. A. Orszag.

Thesis (Ph.D.)--Yale University, 2005.

In this thesis Lattice Boltzmann method (LBM) was used to simulate laminar and turbulent channel flows with the goal of understanding the physics of polymer drag reduction. The following results were obtained: (a) We demonstrate the viability of LBM as a numerical method for channel flow. The form of the plots for the velocity fluctuations and Reynolds stress are quantitatively similar to those obtained in experiments and from simulations using Navier-Stokes equations. (b) A variant of LBM was used for the simulation of dilute polymer solution flow. Extra degrees of freedom were included in LBM to represent polymers. Our model for polymers is macroscopically equivalent to FENE-P model. This model was used for the simulations of turbulent channel flow with polymers (Retau = 209). Drag reduction was observed as in experiments. We measured averaged Reynolds stresses and other physical quantities before and after the polymer addition. The addition of polymers produces reductions in the product uv as well as fluctuations of normal velocity v and spanwise velocity w. In contrast, the streamwise component of the velocity fluctuation u grows moderately. These changes in energy dynamics reproduce the physical phenomena associated with the polymer dynamics in the channel flow. (c) The LBM was extended to simulate non-Newtonian effects of polymers by modifying the relaxation time in LBM. This modification makes the macroscopic viscosity of the fluid depend on the velocity-gradient tensor. When applied to pulsatile laminar flow of concentrated polymer solution, the calculation showed flow enhancement under certain conditions. The result obtained is in agreement with experiments. The same model was used to consider the scenario of drag reduction in turbulent channel flow by spatial modification of viscosity. The example considered is the linear increase of viscosity in a buffer layer up to the core region of the channel. (d) We investigated the effect of the diluted polymer solution on Kelvin-Helmholtz instability. We consider the simple problem of the mixing layer which consists of two horizontal layers of fluids moving relative to each other. The results show that polymers produce stabilizing effect and suppress momentum transport due to fluctuating velocity components. (Abstract shortened by UMI.)

ISBN: 9780542394324Subjects--Topical Terms:

227264
Physics, Fluid and Plasma.

Lattice Boltzmann studies of turbulence in non-Newtonian fluids.
LDR:03329nmm _2200277 _450 001 170940
005 20061228142326.5
008 090528s2005 eng d
020 $a 9780542394324
035 $a 00242970
040 $a UnM $c UnM
100 0 $a Karpikov, Alexander. $3 244971
245 1 0 $a Lattice Boltzmann studies of turbulence in non-Newtonian fluids.
300 $a 146 p.
500 $a Directors: K. R. Sreenivasan; S. A. Orszag.
500 $a Source: Dissertation Abstracts International, Volume: 66-11, Section: B, page: 6043.
502 $a Thesis (Ph.D.)--Yale University, 2005.
520 # $a In this thesis Lattice Boltzmann method (LBM) was used to simulate laminar and turbulent channel flows with the goal of understanding the physics of polymer drag reduction. The following results were obtained: (a) We demonstrate the viability of LBM as a numerical method for channel flow. The form of the plots for the velocity fluctuations and Reynolds stress are quantitatively similar to those obtained in experiments and from simulations using Navier-Stokes equations. (b) A variant of LBM was used for the simulation of dilute polymer solution flow. Extra degrees of freedom were included in LBM to represent polymers. Our model for polymers is macroscopically equivalent to FENE-P model. This model was used for the simulations of turbulent channel flow with polymers (Retau = 209). Drag reduction was observed as in experiments. We measured averaged Reynolds stresses and other physical quantities before and after the polymer addition. The addition of polymers produces reductions in the product uv as well as fluctuations of normal velocity v and spanwise velocity w. In contrast, the streamwise component of the velocity fluctuation u grows moderately. These changes in energy dynamics reproduce the physical phenomena associated with the polymer dynamics in the channel flow. (c) The LBM was extended to simulate non-Newtonian effects of polymers by modifying the relaxation time in LBM. This modification makes the macroscopic viscosity of the fluid depend on the velocity-gradient tensor. When applied to pulsatile laminar flow of concentrated polymer solution, the calculation showed flow enhancement under certain conditions. The result obtained is in agreement with experiments. The same model was used to consider the scenario of drag reduction in turbulent channel flow by spatial modification of viscosity. The example considered is the linear increase of viscosity in a buffer layer up to the core region of the channel. (d) We investigated the effect of the diluted polymer solution on Kelvin-Helmholtz instability. We consider the simple problem of the mixing layer which consists of two horizontal layers of fluids moving relative to each other. The results show that polymers produce stabilizing effect and suppress momentum transport due to fluctuating velocity components. (Abstract shortened by UMI.)
590 $a School code: 0265.
650 # 0 $a Physics, Fluid and Plasma. $3 227264
650 # 0 $a Engineering, Mechanical. $3 212470
690 $a 0548
690 $a 0759
710 0 # $a Yale University. $3 212430
773 0 # $g 66-11B. $t Dissertation Abstracts International
790 $a 0265
790 1 0 $a Orszag, S. A., $e advisor
790 1 0 $a Sreenivasan, K. R., $e advisor
791 $a Ph.D.
792 $a 2005
856 4 0 $u http://libsw.nuk.edu.tw:81/login?url=http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3194667 $z http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3194667