PowerSPECTRUM Examples
Isolation of key flow structures
The technical process of identifying and describing structure within fluid flow data requires visualization, spectral analysis, filtering and technical graphing.
Images & Graphs as in order below:
1. Instantaneous velocity fluctuations shown using velocity magnitude and vectors. The circle indicates the location of a fluid probe behind the spoiler to generate time-series data for spectral analysis.
2. Power spectrum of pressure fluctuations (in dB) at the fluid probe shows a narrow-band peak near 25 Hz.
3. The non-dimensional pressure time-series data at the probe is reconstructed from 20-30 Hz using a band-pass filter.
4. The velocity fluctuations associated with the vortex shedding are reconstructed from 20-30 Hz using a band-pass filter. The results demonstrate the presence of well-organized lateral vortices that show low-frequency shedding, convection, and roll-up.
Crosswind effect:
The effect of high crosswind is shown in this visualization of coherent pressure fluctuations for a vehicle at 30 degree yaw angle (nose is yawed to the left relative to the oncoming wind). A band-pass filter was used to show fluctuations which produce high wind noise levels in the 35-44 Hz frequency range.
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Motorsports:
Motorsports vehicles use wings, blade spoilers, and ground effects to significantly enhance performance and improve down force and stability while minimizing drag. At the same time, these design features create large areas of separated, turbulent and highly dynamic flow. PowerSPECTRUM maps the frequency response of flow structures responsible for maintaining on-track performance.
Design innovation comes from data analysis that isolates critical flow features. Above Left: Coherent turbulent pressure waves are visualized using spectral filtering for a race car on-track simulation. Above Right: Visualization of turbulence energy levels shows the regions of highest fluctuation intensity around the deck spoiler. These visualizations assist in aerodynamic tuning of turbulent zones.
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