Bolund Island#

Bolund Island

1. Project Description#

The objective of this project is to reproduce the wind flow properties over the Bolund Island, as measured on-site by [1]. One convective time scale is defined as \(CTS = H / U_H\), where \(H =\) 12 meters is the nominal height of the island.

The island positioned at the computational domain has the geometry:

Bolund Island geometry

And probes are positioned over the island for velocity measurement:

Bolund Island coordinates

The wind directions chosen to be simulated were:

Wind Directions#

Wind direction

270.0 \(^\circ\)

255.0 \(^\circ\)

239.0 \(^\circ\)

2. Simulation Setup#

The Synthetic Eddy Method (SEM) boundary condition is applied at the inlet of the computational domain. Since it is a category 0 terrain, no fins were necessary to be distributed over the floor.

The domain of interest is at resolution level \(lvl\,4\) of the digital wind tunnel:

Bolund Island Grid

A 1:2 refinement ratio is estabilished between levels, and the simulation parameters at grid \(lvl\,4\) were:

Dimensionless Parameters#

\(\boldsymbol{\Delta x/B}\) (spatial resolution)

6.25e-02

\(\boldsymbol{\Delta t/CTS}\) (temporal resolution)

3.17e-03

exports/\(\boldsymbol{CTS}\) (pressure acquisition frequency)

1.00e+01

\(\boldsymbol{T/CTS}\) (statistical sample size)

4.55e+02

\(\boldsymbol{Re_{H}=U_{H}H/\nu}\)

3.80e+04

The equivalent parameters in full scale are:

Full-scale Parameters#

\(\boldsymbol{\Delta x[m]}\)

0.75

\(\boldsymbol{\Delta t[ms]}\)

3.30

\(\boldsymbol{f[Hz]}\)

9.59

\(\boldsymbol{T[s]}\)

475.00

The computational resources required were:

Computational Resources#

Device

NVIDIA RTX A5500

NVIDIA RTX A5500

NVIDIA RTX A5500

Wind direction

270.0 \(^\circ\)

255.0 \(^\circ\)

239.0 \(^\circ\)

Node count (million)

103.62

107.29

107.31

Allocated memory (Gb)

13.36

13.82

13.82

Ellapsed time (h)

6.33

6.45

6.29

3. Inflow#

The inflow is taken from a measurement at M0.

Bolund Island

4. Results: Velocity and Turbulence Profiles#

Mean velocity and turbulence intensity profiles are measuread at different points for each wind direction chosen and compared against experimental data.

Mean Longitudinal Velocity#

Bolund Island
Bolund Island
Bolund Island

Execution Notes#

Execution Notes#

Execution Date (YYYY-MM-DD)

2024-11-23

Solver Version

1.6.2

Changelog#

  • 30 Jan 2025: Updated results.

  • 26 April 2024: Uploaded point comparisons, simulations executed with Nassu release v1.5.4.