Campbell Graphs

QBlade-EE

This feature is only available in the Enterprise Edition of QBlade.

Campbell graphs can be generated from a set of simulations for which a Modal Analysis has been carried out. Generally, this set of simulations spans over a range of wind speeds or rotational speeds. Across this range, the modes are tracked using the Modal Assurance Criterion (MAC). The modal frequencies and damping ratios are then aggregated and visualized in the Campbell Graph. To generate a Campbell graph, first select a simulation. The set of simulations will consist of all simulations that share the same turbine object as the selected simulation. The Modal Analysis Dock Window in Fig. 125 is used to generate the Campbell diagram.

Fig. 125 The Modal Analysis Dock Window

The user can choose to sort the simulation set based on rotational speed or wind speed (Sort). The value d_f [Hz] specifies the maximum allowable delta in frequency for the same mode between two adjacent operating points during the mode sorting process. from Mode selects the starting mode for generating the Campbell diagram, and num Modes specifies the number of different modes (starting from from Mode) for the Campbell diagram. Clicking on Create Campbell Graph Data then generates the mode shapes. An exemplary Campbell Graph is shown in Fig. 126.

Fig. 126 Campbell Graph showing modal frequencies and damping ratios

Setup for Campbell Graphs

An efficient way to set up Campbell Graphs is using the Design Load Case Generator (see Design Load Case Generation). Choosing the Steady Power Curve standard allows for efficient setup of simulations across a range of wind speeds. Ensure the Modal Analysis feature is activated for each simulation. After generating the simulations from this DLC definition, they can be quickly evaluated using the Multi-Threaded Batch Analysis feature, and subsequently, a Campbell Graph can be generated.

Fig. 127 Setup of Steady Power Curve simulations for modal analysis