### Objectives

This article presents how to use the Load Extrapolation Algorithm (LEA) in a MANATEE simulation to speed-up calculation of electromagnetic loads at variable speed, in particular for early design stages.

Electromagnetic loads are computed from one single simulation and extrapolated to the full speed range, hence only vibroacoustic calculations are repeated at each different speed.

### GUI implementation

TBC

### Scripting implementation

Variable speed calculation based on Load Extrapolation Algorithm is activated in MANATEE with

`Input.Simu.type_varspeed=1`

Input.Simu.type_loadcalc=1

The total number of speed steps to use is specified by

`Input.Simu.Nspeeds=100`

Contrary to speed by speed calculations, a high number of speeds can be used as the computation time is very low when using analytical vibroacoustic models such as in early design stages.

### Plot commands

All the standard variable speed command lines starting with *plot_VS* are available in the Load Extrapolation mode:

- spectrograms, for instance with plot_VS_ASPL_spectrogram
- Order Tracking analysis, for instance with plot_VS_ASWL_order_analysis
- Operational Deflection Shapes, for instance with plot_VS_ODS

### Validation cases

The following validation cases favorably compares the Load Extrapolation Algorithm with speed by speed full NVH calculations: