QBlade Documentation

QBlade [1] is a state of the art multi-physics code, covering the complete range of aspects required for the aero-servo-hydro-elastic simulation of horizontal, or vertical axis wind turbines. This software, developed since 2010, is realized as a modular implementation of highly efficient multi-fidelity aerodynamic, structural dynamic and hydrodynamic solvers in a modern, object oriented C++ framework.

We leverage the current computer architecture by thoroughly utilizing CPU (via OpenMP) and GPU (via OpenCL) parallelization techniques for a high numerical performance. QBlade is a platform independent software, and can be deployed on workstations or clusters running Windows, Unix or MacOS based operating systems. The software is equipped with an intuitive graphical user interface that aids the user during the whole wind turbine design process. All turbine and simulation details are readily available to be accessed and modified in a logical well-structured and tested interface. Simulation results are presented in dynamic graphs that give insight into every simulation detail. Simulations and turbine designs are fully rendered in real time to aid with the comprehension and evaluation of our complex multi-physics models. QBlade enabled the serialization of the complete model data, setup and results into project files to enable simple sharing and collaboration of complex simulation and turbine design projects. The Community Edition of QBlade (QBlade-CE) is freely available under the Academic Public License, while the Enterprise Edition (QBlade-EE) is available under a Commercial License.

QBlade uses a highly optimized and thoroughly validated Lifting Line Free Vortex Wake Method for its aerodynamic calculations. Instead of approximating the wake aerodynamics with a steady-state momentum balance (BEM), the rotor wake is explicitly modeled through Lagrangian vortex elements. This results in a more accurate and detailed spatial and temporal representation (see Marten et al.[2]) of the rotor induction, when compared to BEM approaches, and fully resolves the velocity distribution behind the rotor. This allows to assess wind turbine wake interaction, accurately accounts for the aerodynamics of oscillating floating wind turbine structures and explicitly resolves unsteady vertical axis wind turbine wake dynamics (see Balduzzi et al.[3]). As an alternative with lower computational demand the aerodynamics of horizontal-axis wind turbines can be simulated using an unsteady polar-BEM implementation (see Madsen et al.[4]).

The structural dynamics are modeled in a true multi-body formulation. The sub components of the multi-body model are made up of rigid- or flexible nonlinear Euler beam elements in a corotational formulation. For floating offshore simulations we have integrated cable elements in the absolute nodal coordinate formulation (ANCF) which meet the requirements to effectively model the nonlinear dynamics of complex mooring systems. Both bottom-fixed and floating offshore wind turbine systems can be modeled.

The hydrodynamic loads on the wind turbine’s substructure are calculated either via the potential flow theory, the Morison equation based strip theory or a user defined combination of the two. The integrated potential flow approach also includes the higher order slow drift forces obtained from quadratic transfer functions. QBlade integrates with potential flow data from common software such as the WAMIT, NEMOH or similar toolboxes.