Bożena Żukowska
Noise & Acoustics Engineer — Jet Noise · Acoustics & Vibration
Warsaw, Poland
Noise & Acoustics Engineer specializing in jet noise prediction using CFD-CAA hybrid methods. Computes jet noise spectra and directivity using Large Eddy Simulation coupled with Ffowcs Williams-Hawkings (FWH) acoustic analogy for both turbulent mixing noise and shock-associated broadband/screech noise components. Works closely with propulsion team on exhaust nozzle geometry optimization for noise reduction.
Expertise
- jet noise prediction and shock-associated noise
- CFD-CAA hybrid methods for jet noise
- Ffowcs Williams-Hawkings (FWH) acoustic analogy
- exhaust nozzle acoustic optimization
- turbulent jet noise scaling
Technologies
Work History
2025-02
Jet noise certification prediction methodology validation — correlated CFD-CAA predictions against 3-microphone noise certification flight test data. Assessed systematic biases and defined prediction uncertainty bounds for certification use.
Challenge: Systematic 1.8 EPNdB overprediction of jet noise at approach power was traced to atmospheric refraction effects not included in the FWH far-field propagation model. Including a simplified refraction correction based on ground-level temperature gradient reduced the systematic bias to 0.3 EPNdB.
Learned: CFD-CAA jet noise predictions in the far field require atmospheric refraction corrections for accurate comparison against flight test measurements at approach altitudes. FWH free-field propagation assumes a homogeneous atmosphere — atmospheric refraction at approach angles is a first-order correction that must be included.
2024-06
Exhaust nozzle chevron optimization for jet noise reduction — parametric CFD+CAA study of chevron penetration angle and count for a bypass nozzle at approach power. Quantified noise reduction vs. thrust penalty trade.
Challenge: Chevron noise reduction is a strong function of penetration angle — a 2° angle change gave 1.5 EPNdB variation. But thrust penalty also varied strongly with penetration. Multi-objective Pareto optimization with 2 conflicting objectives (noise reduction + thrust retention) required Pareto front exploration with 48 CFD cases.
Learned: Chevron optimization is inherently multi-objective — maximizing noise reduction and minimizing thrust penalty are conflicting. Set up as a Pareto front exploration from the start. Optimizing for noise reduction alone and then checking thrust penalty typically misses the Pareto-optimal solution.
2023-11
Shock-associated broadband noise analysis for an underexpanded jet condition at high-power sideline — predicted BBSN using the Harper-Bourne/Fisher model and compared against nozzle rig acoustic measurements.
Challenge: Harper-Bourne/Fisher model requires accurate prediction of the shock cell structure in the jet plume. RANS CFD with k-epsilon model underpredicted shock cell length by 20%, leading to incorrect BBSN peak frequency. Switching to the SST model with compressibility correction improved shock cell agreement to within 8%.
Learned: Shock cell structure prediction for BBSN assessment is turbulence model sensitive. The k-epsilon model is insufficient for highly underexpanded jets — SST with compressibility correction is the minimum appropriate turbulence model for shock-cell aeroacoustics.
2023-04
Turbulent jet mixing noise prediction for a bypass nozzle — LES simulation of the jet plume using ANSYS Fluent, followed by FWH surface integration for far-field noise prediction at approach power.
Challenge: LES of the full jet plume at engine-scale Reynolds numbers was computationally prohibitive. Used Reynolds number scaling: ran LES at 1/10th scale with appropriate Reynolds number corrections applied to the far-field noise using Power Spectral Density scaling laws.
Learned: Full-scale LES of turbofan jet noise is computationally impractical. Reynolds-scaled LES with appropriate acoustic scaling corrections is the accepted methodology — document the scaling approach and its validation limits explicitly, as the corrections have known accuracy limitations at high bypass ratio conditions.