DNS 1-2 Description: Difference between revisions

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computational setup to make the computations feasible and avoid uncertainty or ambiguity.
computational setup to make the computations feasible and avoid uncertainty or ambiguity.
= Description of the test case =
= Description of the test case =
An idealised channel flow, without side walls, is considered. The details of the case are given in [https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/identifying-eigenmodes-of-averaged-smallamplitude-perturbations-to-turbulent-channel-flow/EF03E2FFFF1A481FC55448B3F11496F2 Iyer et al.(2019)]. The current set of simulations has a higher grid resolution in the wall normal direction.  
An idealised channel flow, without side walls, is considered. The details of the case are given in [https://www.cambridge.org/core/journals/journal-of-fluid-mechanics/article/identifying-eigenmodes-of-averaged-smallamplitude-perturbations-to-turbulent-channel-flow/EF03E2FFFF1A481FC55448B3F11496F2 Iyer et al.(2019)]<ref name="iyer2019">'''A. Iyer, F. D. Witherden, S. I. Chernyshenko and P. E. Vincent''', Identifying eigenmodes of averaged small-amplitude perturbations to turbulent channel flow, Journal of Fluid Mechanics, 875 (758-780), 2019</ref>. The current set of simulations has a higher grid resolution in the wall normal direction.  
==Geometry and flow parameters==
==Geometry and flow parameters==
The geometry is a cuboid of dimensions <math>8\pi</math> units in the streamwise direction <math>(x)</math>, 2 units in the transverse direction <math>(y)</math> and <math>4\pi</math> units in the spanwise direction <math>(z)</math>. The dimensions are normalised by the channel half-width, <math>h</math> and centreline velocity.  
The geometry is a cuboid of dimensions <math>8\pi</math> units in the streamwise direction <math>(x)</math>, 2 units in the transverse direction <math>(y)</math> and <math>4\pi</math> units in the spanwise direction <math>(z)</math>. The dimensions are normalised by the channel half-width, <math>h</math> and centreline velocity.  
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'''References'''
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{{ACContribs
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| authors=Arun Soman Pillai, Lionel Agostini
| authors=Arun Soman Pillai, Lionel Agostini

Revision as of 05:57, 7 October 2021


Front Page

Description

Computational Details

Quantification of Resolution

Statistical Data

Instantaneous Data

Storage Format

Introduction

The turbulent Channel Flow is one of the canonical flows used to study turbulence in wall bounded turbulence. DNS of turbulent channel flow were undertaken at . DNS were undertaken using PyFR (http://www.pyfr.org/) version 1.12.0:

  • based on the high-order flux reconstruction method of Huynh
  • compressible solver
  • a Rusanov Riemann solver was employed to calculate the inter-element fluxes
  • an explicit RK45[2R+] scheme was used to advance the solution in time
  • Fifth order polynomials are used for the computations

Review of previous studies

Provide a brief review of related past studies, either experimental or computational. Identify the configuration chosen for the present study and position it with respect to previous studies. If the test case is geared on a certain experiment, explain what simplifications ( e.g. concern- ing geometry, boundary conditions) have been introduced with respect to the experiment in the computational setup to make the computations feasible and avoid uncertainty or ambiguity.

Description of the test case

An idealised channel flow, without side walls, is considered. The details of the case are given in Iyer et al.(2019)[1]. The current set of simulations has a higher grid resolution in the wall normal direction.

Geometry and flow parameters

The geometry is a cuboid of dimensions units in the streamwise direction , 2 units in the transverse direction and units in the spanwise direction . The dimensions are normalised by the channel half-width, and centreline velocity.

Boundary conditions

The domain is periodic in the streamwise and spanwise directions which gives a flow developing in time. The transverse boundaries are viscous walls with no-slip boundary conditions. The initial density and pressure fields are uniform. The initial velocity field is . The solution is started at order 2 and progressively increased to order 5.


References

  1. A. Iyer, F. D. Witherden, S. I. Chernyshenko and P. E. Vincent, Identifying eigenmodes of averaged small-amplitude perturbations to turbulent channel flow, Journal of Fluid Mechanics, 875 (758-780), 2019


Contributed by: Arun Soman Pillai, Lionel Agostini — Imperial College London

Front Page

Description

Computational Details

Quantification of Resolution

Statistical Data

Instantaneous Data

Storage Format


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