Abstract
The main aim of this document is to detail the numerical simulation of statistically fully-developed
turbulent pipe flow using Nek5000 [2] and also to explain how the turbulence statistics can be obtained.
In the streamwise direction, z, periodic boundary condition is applied. Additionally, the flow in the
azimuthal direction θ is statically homogeneous. Therefore, by averaging in z, θ, and time the resulting
profiles (shown by h·i) are 1D and vary only with the radial (wall-normal) coordinate r. Note that the
radial coordinate is defined from r = 0 (at the pipe center) to r = R (at the wall), where R is the radius
of the pipe. We also define the wall distance y = R − r.
In the next section, an overview is given on different directories included in the Nek5000 case for
fully-developed pipe flow. In Section 3, the required steps to setup a simulation including generating the
mesh are briefly explained. This is followed by Section 4 where the details for obtaining 1D profiles of
turbulence statistics are provided. Finally in Section 5, a set of sample results are presented.
The algorithm to compute the statistics has been refined over the years, starting with the work by
El Khoury et al. [3] and Noorani et al. [6] for straight and bent pipes, respectively. The actual routines
are adapted from [9] and simplified for the one-dimensional statistics used in fully-developed pipe flow
turbulent pipe flow using Nek5000 [2] and also to explain how the turbulence statistics can be obtained.
In the streamwise direction, z, periodic boundary condition is applied. Additionally, the flow in the
azimuthal direction θ is statically homogeneous. Therefore, by averaging in z, θ, and time the resulting
profiles (shown by h·i) are 1D and vary only with the radial (wall-normal) coordinate r. Note that the
radial coordinate is defined from r = 0 (at the pipe center) to r = R (at the wall), where R is the radius
of the pipe. We also define the wall distance y = R − r.
In the next section, an overview is given on different directories included in the Nek5000 case for
fully-developed pipe flow. In Section 3, the required steps to setup a simulation including generating the
mesh are briefly explained. This is followed by Section 4 where the details for obtaining 1D profiles of
turbulence statistics are provided. Finally in Section 5, a set of sample results are presented.
The algorithm to compute the statistics has been refined over the years, starting with the work by
El Khoury et al. [3] and Noorani et al. [6] for straight and bent pipes, respectively. The actual routines
are adapted from [9] and simplified for the one-dimensional statistics used in fully-developed pipe flow
| Original language | English |
|---|---|
| Publication status | Published - Dec 2019 |