Mesoscale to Microscale Coupling for Wind Energy Applications: What Features of the Offshore Environment are Needed for Multi-scale Modeling?

The purpose of the US DOE’s Mesoscale-Microscale Coupling (MMC) Project is to develop, verify, and validate physical models and modeling techniques that bridge the most important atmospheric scales that determine wind plant performance and reliability. The project seeks to create a new predictive numerical simulation capability that represents a range of dynamic atmospheric flow conditions impacting wind plant performance. The project has made numerous impacts on understanding and modeling the so-called terra incognita, that grid resolution between about 100 m and the boundary layer depth at which numerical artifacts are often difficult to distinguish from physical boundary layer rolls, developing and testing novel coupling methods, rigorously comparing methods to initialize turbulence at the microscale, modeling the surface layer appropriately, as well as assessing the results and quantifying the uncertainty using metrics most appropriate to wind energy.

Most recently, the MMC project team seeks to perform coupled simulations of the offshore wind environment. This environment brings its own unique issues that must be considered. Land-ocean interactions produce sea and land breezes. The type and age of wave impacts the wind above it, with that impact becoming much more important as scales decrease. Small-scale ocean fronts alter heat and momentum transfer to the atmospheric environment. This talk will discuss these issues and how the team is moving forward to couple the mesoscale to the microscale while modeling and parameterizing these important ocean-atmosphere coupling features. These simulations are expected to provide the wind industry new tools that can be used in the planning, design, layout, and optimization of offshore wind plants, thus facilitating deploying higher capacities of wind generation in the offshore environment.