Publications
Refereed journal publications
2025
Dacome, G., Lazzarini, L., Talamelli, A., Bellani, G., Baars, W.J. (2025) Scaling of wall-pressure--velocity correlations in high Reynolds number turbulent pipe flow. J. Fluid Mech. in press. arXiv link
Cuellar, A., Amico, E., Serpieri, J., Cafiero, G., Baars, W.J., Discetti, S., Ianiro, A. (2025) Measuring time-resolved heat transfer fluctuations on a heated-thin foil in a turbulent channel airflow. Meas. Sci. Technol., online. doi link
2024
Goudswaard, R.J., Ragni, D., Baars, W.J. (2024) Effects of the rotor tip gap on the aerodynamic and aeroacoustic performance of a ducted rotor in hover. Aerosp. Sci. Technol. 155, 109734. doi link
Hassanein, A, Modesti, D., Scarano, F., Baars, W.J. (2024) Interaction of an inner-scaled Helmholtz resonator with boundary-layer turbulence. Phys. Rev. Fluids 9, 114610. doi link
Dacome, G., Siebols, R., Baars, W.J. (2024) Small-scale Helmholtz resonators with grazing turbulent boundary layer flow. J. Turbul. 25:12, 461-481. doi link
Dacome, G., Mörsch, R., Kotsonis, M., Baars, W.J. (2024) Opposition flow control for reducing skin-friction drag of a turbulent boundary layer. Phys. Rev. Fluids 9, 064602. doi link
Baars, W.J., Ragni, D. (2024) Low-frequency intensity modulation of high-frequency rotor noise. AIAA J. 62:9, 3374-3390. doi link
Baars, W.J., Dacome, G., Lee, M. (2024) Reynolds-number scaling of wall-pressure--velocity correlations in wall-bounded turbulence. J. Fluid Mech. 981, A15. doi link
2023
Li, M., Baars, W.J., Marusic, I., Hutchins, N. (2023) Quantifying inner-outer interactions in non-canonical wall-bounded flows. Phys. Rev. Fluids 8, 084602. doi link
Carrasco Grau, J., van Campenhout, O.W.G., Hartog, F.H., van Nesselrooij, M., Baars, W.J., Schrijer, F.F.J. (2023) Experimental investigation into the drag performance of chevron-shaped protrusions in wall-bounded turbulence. Flow Turbul. Combust. Online. doi link
Dekker, H.N.J., Baars, W.J., Scarano, F., Tuinstra, M., Ragni, D. (2023) Unsteady flow behaviour of multi-rotors in ground proximity. Flow 3, E30. doi link
2022
Li, X., Hutchins, N., Zheng, X., Marusic, I., Baars, W.J. (2022) Scale-dependent inclination angle of turbulent structures in stratified atmospheric surface layers. J. Fluid Mech. 942, A38. doi link
Ragni, D., Fiscaletti, D., Baars, W.J. (2022) Jet noise predictions by time marching of single-snapshot tomographic PIV fields. Exp. Fluids 63:84, 1-18. doi link
Dekker, H.N.J., Ragni, D., Baars, W.J., Scarano, F., Tuinstra, M. (2022) Aerodynamic interactions of side-by-side rotors in ground proximity. AIAA J. 60:7, 4267-4277. doi link
2021
Baars, W.J., Murray, N.E., Tinney, C.E. (2021) A proper framework for studying noise from jets with non-compact sources. J. Fluid Mech. 929, A23. doi link
Berghout, P., Baars, W.J., Krug, D. (2021) The large-scale footprint in small-scale Rayleigh-Bénard turbulence. J. Fluid Mech. 911, A62. doi link
2020
Samie, M., Baars, W.J., Rouhi, A., Schlatter, P., Örlü, R., Marusic, I., Hutchins, N. (2020) Near wall coherence in wall-bounded flows and implications for flow control. Int. J. Heat Fluid Flow 86, 108683. doi link
Martelli, E., Saccoccio, L. Ciottoli, P.P., Tinney, C.E., Baars, W.J., Bernardini, M. (2020) Flow dynamics and wall-pressure signatures in a high-Reynolds-number overexpanded nozzle with free shock separation. J. Fluid Mech. 895, A29. doi link
Baars, W.J., Marusic, I. (2020) Data-driven decomposition of the streamwise turbulence kinetic energy in boundary layers. Part 1. Energy spectra. J. Fluid Mech. 882, A25. doi link
Baars, W.J., Marusic, I. (2020) Data-driven decomposition of the streamwise turbulence kinetic energy in boundary layers. Part 2. Integrated energy and A1. J. Fluid Mech. 882, A26. doi link
2019
Baidya, R., Baars, W.J., Zimmerman, S., Samie, M., Hearst, R.J., Dogan, E., Mascotelli, L., Zheng, X., Bellani, G., Talamelli, A., Ganapathisubramani, B., Hutchins, N., Marusic, I., Klewicki, J., Monty, J.P. (2019) Simultaneous skin friction and velocity measurements in high Reynolds number pipe and boundary layer flows. J. Fluid Mech. 871, 377-400. doi link
Krug, D., Baars, W.J., Hutchins, N., Marusic, I. (2019) Vertical coherence of turbulence in the atmospheric surface layer: connecting the hypotheses of Townsend and Davenport. Bound.-Layer Meteorol. 172:2, 199-214. doi link
2017
Marusic, I., Baars, W.J., Hutchins, N. (2017) Scaling of the streamwise turbulence intensity in the context of inner-outer interactions in wall-turbulence. Phys. Rev. Fluids 2, 100502. doi link
Baars, W.J., Hutchins, N., Marusic, I. (2017) Self-similarity of wall-attached turbulence in boundary layers. J. Fluid Mech. 823, R2. doi link
Abbassi, M.R., Baars, W.J., Hutchins, N., Marusic, I. (2017) Skin-friction drag reduction in a high-Reynolds-number turbulent boundary layer via real-time control of large-scale structures. Int. J. Heat Fluid Flow 67, 30-41. doi link
Baars, W.J., Hutchins, N., Marusic, I. (2017) Reynolds-number trend of hierarchies and scale interactions in turbulent boundary layers. Phil. Trans. R. Soc. A 375:20160077. doi link
2016
Squire, D.T., Baars, W.J., Hutchins, N., Marusic, I. (2016) Inner—outer interactions in rough-wall turbulence. J. Turbulence 17:12, 1159-1178. doi link
Baars, W.J., Hutchins, N., Marusic, I. (2016) Spectral stochastic estimation of high-Reynolds-number wall-bounded turbulence for a refined inner-outer interaction model. Phys. Rev. Fluids 1, 054406. doi link | data & scripts available
Baars, W.J., Tinney, C.E., Hamilton, M.F. (2016) Piecewise-spreading regime model for calculating effective Gol'dberg numbers for supersonic jet noise. AIAA J. 54:9, 2833-2842. doi link | script available
Baars, W.J., Squire, D.T., Talluru, K.M., Abbassi, M.R., Hutchins, N., Marusic, I. (2016) Wall-drag measurements of smooth- and rough-wall turbulent boundary layers using a floating element. Exp. Fluids 57:5, 90, 1-16. doi link | data available
Fiévet, R., Tinney, C.E., Baars, W.J., Hamilton, M.F. (2016) Coalescence in the sound field of a laboratory scale supersonic jet. AIAA J. 54:1, 254-265. doi link
2015
Baars, W.J., Talluru, K.M., Hutchins, N., Marusic, I. (2015) Wavelet analysis of wall turbulence to study large-scale modulation of small scales. Exp. Fluids 56:10, 188, 1-15. doi link
Baars, W.J., Ruf, J.H., Tinney, C.E. (2015) Non-stationary shock motion unsteadiness in an axisymmetric geometry with pressure gradient. Exp. Fluids 56:5, 92, 1-18. doi link
2014
Donald, B.W., Baars, W.J., Tinney, C.E., Ruf, J.H. (2014) The sound from large area ratio nozzles during fixed and transient operations. AIAA J. 52:7, 1474-1485. doi link
Baars, W.J., Tinney, C.E., Wochner, M.S., Hamilton, M.F. (2014) On cumulative nonlinear acoustic waveform distortions from high-speed jets. J. Fluid Mech. 749, 331-366. doi link
Baars, W.J., Tinney, C.E. (2014) Proper orthogonal decomposition-based spectral higher-order stochastic estimation. Phys. Fluids 26, 055112, 1-20. doi link
Baars, W.J., Tinney, C.E. (2014) Shock-structures in the acoustic field of a Mach 3 jet with crackle. J. Sound Vibr. 333:12, 2539-2553. doi link
2013 and prior
Baars, W.J., Tinney, C.E. (2013) Transient wall pressures in an overexpanded and large area-ratio nozzle. Exp. Fluids 54:2, 1468, 1-17. doi link
Baars, W.J., Tinney, C.E., Ruf, J.H., Brown, A.M., McDaniels, D.M. (2012) Wall pressure unsteadiness and side loads in overexpanded rocket nozzles. AIAA J. 50:1, 61-73. doi link
Baars, W.J., Stearman, R.O., Tinney, C.E. (2010) A review on the impact of icing on aircraft stability and control. J. Aeroelast. Struct. Dyn. 2:1, 35-52. doi link
Dacome, G., Lazzarini, L., Talamelli, A., Bellani, G., Baars, W.J. (2023) Turbulent wall-pressure fluctuations in the CICLoPE facility. Progress in Turbulence X. iTi 2023. Springer Proceedings in Physics, vol 404. doi link
Foroozan, F., Ianiro, A., Discetti, S., Baars, W.J. (2023) Estimation of boundary layer turbulence through non-intrusive sensing of wall-temperature fluctuations. iTi Conference on Turbulence x, Bertinoro, Italy.
Formidabile, M., Baars, W.J., Schrijer, F.F.J. (2023) Effect of aeroelasticity on the acoustic signature of TOP contoured rocket nozzles in overexpanded conditions. 10th EUCASS - 9th CEAS Aerospace Europe Conference, Lausanne, Switzerland. proceedings pdf
Dekker, H.N.J., Tuinstra, M., Baars, W.J., Scarano, F., Ragni, D. (2023) Aeropropulsive performance modelling of over-the-wing propulsion at incidence. AIAA-2023-3355. doi link.
Baars, W.J., Ragni, D. (2023) Low-frequency intensity modulation of high-frequency rotor noise. AIAA-2023-3215. doi link.
Baars, W.J., Lee, M. (2022) Wall-pressure--velocity transfer kernel in high Reynolds number turbulent channel flows. 12th Intnl. Symposium on Turbulence and Shear Flow Phenomena (TSFP-12), Osaka, Japan. proceedings pdf
Kempaiah K.K., Sem, J., Baars, W.J. (2022) Large-scale flow organization of wall-bounded turbulence over flush-mounted rotating discs. 12th Intnl. Symposium on Turbulence and Shear Flow Phenomena (TSFP-12), Osaka, Japan. proceedings pdf
Baars, W.J., Grande, E., Ragni, D. (2022) Noise metrics of the time-varying acoustic far-field of rotors. NOISE-CON 2022, Lexington, KY, U.S.A. doi link
Baars, W.J., Grande, E., Ragni, D. (2021) Time-varying aspects of the acoustic field of a small-scale rotor. DICUAM 2021, Delft, The Netherlands.
Dekker, H.N.J., Ragni, D., Baars, W.J., Scarano, F., Tuinstra, M. (2021) Three-dimensional flow topology of a multi-rotor in ground effect. DICUAM 2021, Delft, The Netherlands. proceedings pdf
Tinney, C.E., Baars, W.J. (2021) Supersonic jet noise phenomena and crackle. VKI Lecture Series STRATOFLY. link
Baars, W.J., Bullard, L., Mohamed, A. (2021) Quantifying modulation in the acoustic field of a small-scale rotor using bispectral analysis. AIAA-2021-0713. doi link
Pedersen, M.T., Murray, N.E., Baars, W.J. (2020) Modeling supersonic jet noise exposure using a data-informed wave packet approach. AIAA-2020-2605. doi link
Baars, W.J., Krug, D., Hutchins, N., Marusic, I. (2019) Vertical coherence of turbulence in the atmospheric surface layer. 17th European Turb. Conf., Torino, Italy.
Murray, N.E., Baars, W.J. (2019) Passive nozzle-based technology for the reduction of heated supersonic jet noise. AIAA-2019-2729. Delft, The Netherlands. doi link
Ruan, Z., Baars, W.J., Hutchins, N., Marusic, I. (2019) Role of large-scales on turbulence skin-friction in high-Reynolds-number turbulent boundary layers. European Drag Reduction and Flow Control Meeting, ERCOFTAC, Bad Herrenalb, Germany.
Ruan, Z., Baars, W.J., Abbassi, M.R., Hutchins, N., Marusic, I. (2018) Active conrol of large-scales in a high-Reynolds-number turbulent boundary layer. 21st Australasian Fluid Mech. Conf., Adelaide, Australia. proceedings pdf
Baars, W.J., Hutchins, N., Marusic, I. (2017) Wall-coherent structure of turbulent boundary layers: an empirical spectral filter. 16th European Turb. Conf., Stockholm, Sweden.
Abbassi, M.R., Baars, W.J., Hutchins, N., Marusic, I. (2016) Drag reduction via large-scale opposition flow control in a high-Reynolds-number turbulent boundary layer. 20th Australasian Fluid Mech. Conf., Perth, Australia. proceedings pdf
Marusic, I., Baars, W.J., Hutchins, N. (2015) An extended view of the inner-outer interaction model for wall-bounded turbulence using spectral linear stochastic estimation. Proc. Engineering, 126, 24-28. doi link
Baars, W.J., Talluru, K.M., Hutchins, N., Marusic, I. (2015) Wavelet analysis of broadband signals to extract amplitude and frequency modulation: an application to wall turbulence. 15th European Turb. Conf., Delft, The Netherlands. proceedings pdf
Baars, W.J., Talluru, K.M., Bishop, B.J., Hutchins, N., Marusic, I. (2014) Spanwise inclination and meandering of large-scale structures in a high-Reynolds-number turbulent boundary layer. 19th Australasian Fluid Mech. Conf., Melbourne, Australia. proceeding pdf
Baars, W.J., Tinney, C.E., Hamilton, M.F. (2014) Challenges associated with studying nonlinear distortion of acoustic waveforms emitted by high-speed jets. Internoise 2014, Melbourne, VIC, Australia (invited). proceedings pdf
Fiévet, R., Tinney, C.E., Baars, W.J., Hamilton, M.F. (2014) Acoustic waveforms produced by a laboratory scale supersonic jet. AIAA-2014-2906, Atlanta, GA, USA. doi link
Baars, W.J., Tinney, C.E. (2014) Temporal and spectral quantification of the ‘crackle’ component in supersonic jet noise. In Y. Zhou et al. (eds.), Fluid-Structure-Sound Interactions and Control, Lecture Notes in Mech. Eng., Springer-Verslag, Berlin, Proc. 2nd Symp. on Fluid-Structure-Sound Interactions and Control, Hong Kong & Macau, China. doi link
Baars, W.J., Tinney, C.E. (2013) Quantifying crackle-inducing acoustic shock-structures emitted by a fully-expanded Mach 3 jet. AIAA-2013-2081, Berlin, Germany. doi link
Baars, W.J., Tinney, C.E. (2013) Time preserved jet crackle quantification. Texas Fluid Dynamics Meeting, Lake Buchanan, TX, USA.
Murray, N.E., Lyons, G., Tinney, C.E., Donald, B.W., Baars, W.J., Thurow, B., Haynes, H., Panickar, P. (2012) A laboratory framework for synchronous near/far-field acoustics and MHz PIV in high-temperature shock-containing jets. ASME/NCAD2012-1270, 505-519, Proc. Internoise 2012, New York, NY, USA. doi link
Baars, W.J., Tinney, C.E., Wochner, M.S. (2012) Nonlinear noise propagation from a fully expanded Mach 3 jet. AIAA-2012-1177, Nashville, TN, USA. doi link
Donald, B.W., Baars, W.J., Tinney, C.E., Ruf, J.H. (2012) Acoustic characterization of sub-scale rocket nozzles. AIAA-2012-0544, Nashville, TN, USA. doi link
Baars, W.J., Tinney, C.E., Ruf, J.H. (2011) Time-frequency analysis of rocket nozzle wall pressures during start-up transients. J. Phys. Conf. Ser., 318, 092001, Proc. 13th European Turb. Conf., Warsaw, Poland. doi link
Baars, W.J., Tinney, C.E., Murray, N.E., Jansen, B.J., Panickar, P. (2011) The effect of heat on turbulent mixing noise in supersonic jets. AIAA-2011-1029, Orlando, FL, USA. doi link
Baars, W.J., Tinney, C.E., Ruf, J.H., Brown, A.M., McDaniels, D.M. (2010) On the unsteadiness associated with shock-induced separation in overexpanded rocket nozzles. AIAA-2010-6728, Nashville, TN, USA. doi link
Baars, W.J., Tinney, C.E., Powers, E.J. (2010) POD based spectral higher-order stochastic estimation. AIAA-2010-1292, Orlando, FL, USA. doi link
Baars, W.J., Tinney, C.E., Stearman, R.O. (2009) Higher-order statistical analysis of stability upsets induced by elevator horn icing. AIAA-2009-3770, San Antonio, TX, USA. doi link
Baars, W.J., Stearman, R.O., Tinney, C.E. (2009) Wind tunnel studies employing higher order statistics to detect ice-induced upsets. IFASD-2009-012, Seattle, WA, USA.
Seminar recordings
Baars, W.J. (Oct. 2023) Importance of the nonlinearity in pressure fluctuations for turbulence control and rotor noise perception. Southampton Aero & Astro Seminars, watch online.
Baars, W.J. (Feb. 2023) Preserving time in the analyses of jet noise and rotorcraft acoustics. Aeroacoustics Webinar, The UK Acoustics Network, watch online.
Baars, W.J. (Sep. 2020) Spectral properties of turbulence kinetic energy in turbulent boundary layers. Australasian Fluid Mechanics Seminar Series, watch online.