1. Atmosphere and Energy Research Group (AERG) Cristina Archer Niranjan Ghaisas Shengbai Xie Chi Yan Yang Pan High-Performance Computing Symposium, University of Delaware, 28 January 2015

2. Outline Overview: 1.Our wind energy research 2.Computational tools 3.Why Mills? 4.Lessons learned Individual talks: – Shengbai: Single-turbine simulations; – Niranjan: Multi-turbine simulations; – Chi: Theoretical framework; – Yang: Turbines-hurricane feedbacks.

4. 1. Our wind energy research Wind turbine wake effects; Turbines-hurricane interactions; New theoretical framework for studying atmospheric turbulence.

5. Single- and multi-turbine wakes In-house code WiTTS (Wind Turbine and Turbulence Simulator)

6. Single- and multi-turbine wakes In-house code WiTTS (Wind Turbine and Turbulence Simulator) OpenFOAM-based SOWFA (Software for Offshore/onshore Wind Farm Applications) Both are Large-Eddy Simulation (LES) codes

7. Turbines-hurricane interactions

8. NO TURBINES WITH TURBINES

9. Non-incompressible, non-Boussinesq (NINB) framework Incompressible assumption: Boussinesq assumption:

10. Non-incompressible, non-Boussinesq (NINB) framework Incompressible assumption: Boussinesq assumption:

11. Non-incompressible, non-Boussinesq (NINB) framework Incompressible assumption: Boussinesq assumption: NINB Navier-Stokes equation:

12. 2. Computational tools vs. topics Wake effects Turbines-hurricane NINB framework

13. 2. Computational tools vs. topics WiTTS SOWFA/OpenFOAM WRF Wake effects Turbines-hurricane NINB framework

14. 2. Computational tools vs. topics WiTTS SOWFA/OpenFOAM WRF Wake effects Turbines-hurricane NINB framework

15. WiTTS Wind Turbine and Turbulence Simulator; Under development in-house; FORTRAN 77, MPI parallelized in 3 directions; Combines an atmospheric boundary layer (ABL) solver and an actuator line model for the wind turbine blades; Tested for incompressible ABL under neutral, stable, and unstable conditions with and without a single turbine.

16. SOWFA Software for Offshore/onshore Wind Farm Applications; Developed by the National Renewable Energy Lab (NREL) using OpenFOAM’s C++ libraries; LES code for atmospheric boundary layer (ABL) with advanced treatment of wind turbines; Website: https://nwtc.nrel.gov/SOWFA

17. WRF Weather Research and Forecasting model; Most widely used mesoscale numerical weather prediction model (>25,000 users); Developed by NCAR/NOAA/FSL/NRL and supported by NCAR for free; Advanced physics, dynamics, numerics; Global to small (~1 km) scale; Website: http://www.wrf-model.org/index.php

19. 3. Why Mills? All models need large disk space and memory, thus multi-processor, parallel environment necessary; Complex setup, with multi-users and multi- versions of codes, libraries, compilers; Post-processing and data display with graphic software require large memory and disk space too; Need support for maintenance, upgrades, security, etc.

20. 4. Lessons learned Valet packages are great; Involve IT early; System versions are better than user versions; Adopt early a file and directory naming convention; Request to be notified about node failures or reboots; Name log files with $JOBID so they do not get overwritten; Be afraid of, and ready for, big system upgrades!