Develop and Validate a Reliable Scale Adaptive Simulation Approach for Wind Turbine Technology

• Applicant: Dr.-Ing. Amirfarhang Mehdizadeh
• Subject Area: Fluid Mechanics
• Term: from 2013 to 2015
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 237600408

• Final Report Year: 2015

Final Report Abstract

Reynolds averaged Navier-Stokes equations (RANS) models are generally used to simulate high Reynolds number turbulent flows relevant for industrial applications. However, RANS methods are not designed to capture the essential unsteady dynamics in complex flows. Large eddy simulation (LES) is an alternative approach that provides space-time accurate solutions, but LES is not feasible for many engineering applications due to its high computational cost. Hybrid URANS-LES modeling approaches can provide reasonable intermediate strategies, however, hybrid approaches present their own modeling issues. The focus of this research program was on the Scale Adaptive Simulation (SAS) hybrid methods which use models based on the Rotta transport equation for turbulent integral length scale to transition from URANS mode to scale resolving mode. Central issue associated with these approaches (i.e. dynamic triggering mechanism regarding attached/Mildly separated flows relevant for wind turbine blade simulation) has been identified and some improvements on the SAS approach are introduced that significantly improve the prediction of S809 airfoil (S809 is a thick airfoil specifically designed for wind turbine applications).

Publications

• (2014), A new formulation of scale adaptive simulation approach to predict complex wall bounded shear flows, Journal of Turbulence, Vol.15, Issue 10, pp 629-649
  Mehdizadeh, A.; Foroutan, H.; Vijayakumar, G. & Sadiki, A.
  
• (2014), Prediction and analysis of interaction between non-steady transition and separation on an oscillating S809 airfoil, 2nd Symposium on OpenFOAM in Wind Energy, May 19-21, Boulder, Colorado, USA
  Nandi T., Brasseur J.G., Mehdizadeh A., Jayaraman B., Paterson E.G.
  
• (2015), A grid base zonal formulation of K −ω −SST −SAS model for complex turbulent flows, 8th International Symposium on Turbulence, Heat and Mass Transfer, September 15-18, Sarajevo, Bosnia and Herzegovina
  . Mehdizadeh, A., Vijayakumar, G., Foroutan, H. and Sadiki, A.
  
• (2015), Analysis of hybrid RANS/LES methods based on the Rotta length scale transport equation. Advances in Hybrid RANS-LES Modeling,Notes on Numerical Fluid Mechanics and Multidisciplinary Design
  Mehdizadeh, A.; Brasseur, J. G.; Nandi, T. & Foroutan, H.
  
• (2015), Integration of Trigger and Grid to Improve the Transition from URANS to LES in Hybrid URANS-LES, International Conference on Model Integration across Disparate Scales in Complex Turbulent Flow Simulation, June 15-17, State College, PA, USA
  Mehdizadeh, A., Brasseur, J. G.