The Gyroscopic Effect
This post covers one of the fundamental issues that makes rotordynamics a unique subject: The Gyroscopic Effect. The gyroscopic effect can be observed in the behavior of spinning tops, fidget...
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When designing a turbomachine, the best analytical approach is not necessarily the most accurate method possible, but the one that will generate the best candidate design in the time and budget available. It makes little sense to do analytical work down to a 1/10% accuracy, while ignoring candidate designs that might yield improvements 20 times that amount if they were considered in the first place. Mastering the art of modern engineering requires an intuitive sense for the cost and accuracy of a given analytical method, and knowing when to move between them.
The figure below shows a distribution of the myriad of various analytic tools that can be applied to turbomachinery design. Note that both the vertical and horizontal axis are logarithmic in scale. Also, note that the vertical axis (error bar) changes much more slowly compared to the horizontal axis (solution time) indicating the diminished return available when moving to progressively more complex methods.
The values are representative of the error and solution time (in seconds) that a particular approach might take. Of course, actual times will vary significantly depending on the complexity of the design, the specific tools applied, and expertise of the user.
It is essential that a variety of these methods be available to the turbomachinery engineer when developing state-of-the-art designs. Other techniques also come into the picture such as: effective pre- and post-processing tools, efficient methods for laying out candidate geometries, optimization procedures for selecting the best combinations of inputs, and manufacturing tools for successful hardware production. Concepts NREC offers all of these advantages and the full range of analytical tools shown in the figure above that are required for cost effective turbomachinery design.
