Waterfall to Order-Cut scenario (Simcenter Nastran FEM acoustics and Acoustics BEM)

The Waterfall to Order-Cut post-processing scenario lets you extract order-cut curves from a 2.5D scenario display, such as a color map of waterfall data of RPM-dependent acoustic or vibro-acoustic results, and display them in an XY plot in a separate view. This allows you to investigate order-related evolutions of the displayed quantity. Orders track the relationship between the acoustic or vibration response at certain amplitude (acoustic pressure, acceleration, and so on), RPM, and rotational frequency.

Note:

A 2.5D scenario display is a two-dimensional plot, where the Z values (for example, pressures) are an attribute of each XY (for example, frequency versus RPM) pair. You can look at the 2.5D plot as a three-dimensional representation reduced to a two-dimensional one.

You can create the Waterfall to Order-Cut plot from the 2.5D scenario display or from the Scenario Based Data-Visualization Navigator. For more information, see Plot order-cut curves.

The order-cut XY plot refreshes in realtime as the order changes in the color map.

Color map of waterfall data	First order-cut XY plot

Parameters

The following table lists the parameters available for defining Waterfall to Order-Cut post-processing scenarios. They appear in the Parameters node of the Scenario Based Data-Visualization Navigator.

Parameter	Description
Order Number	Sets an order number to compute the XY values of order-cut curves from waterfall data of RPM-dependent results. For example, a 4-stroke engine primarily produces high contributions at every even order (order-increment = 2). However, a gearbox with 52 and 39 gear teeth generates high contributions at every multiple of 0.75 (52 / 39).
Method	Specifies the method for the order-cut calculation. The default method is Interpolation, which computes the interpolated value at the selected order.All other methods compute the amplitude of the order section as an RSS calculation of the input data over a specified frequency band, and the phase is the phase at the center frequency of the frequency band.
Order Bandwidth	Available when Method is set to Order Bandwidth.Sets an order value that the software uses to create a fixed order bandwidth. The frequency bandwidth increases with a higher RPM value.
Percentage	Available when Method is set to Percentage of Order.Sets a percentage of the defined order that is used to define the bandwidth. The requirement is that the bandwidth is higher for higher orders. The frequency bandwidth increases with a higher RPM value.
Frequency Bandwidth	Available when Method is set to Frequency Bandwidth.Sets a fixed frequency bandwidth and the corresponding unit.
Number of Frequency Lines	Available when Method is set to Spectral Lines.Sets a fixed number of frequency lines that are used to define the bandwidth.

How do I

Plot order-cut curves

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Waterfall to Order-Cut scenario (Simcenter Nastran FEM acoustics and Acoustics BEM), Simcenter 3D 2021.1 Series

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