Experimental Aerodynamics and Propulsion Lab

Stefano Discetti & Andrea Ianiro.

Aeroreactor LabPIV WindTunnel

Dr. Stefano Discetti and Dr. Andrea Ianiro are experimentalists with expertise in flow diagnostics (Flow visualization; Hot wire anemometry; IR Thermography; Planar, Stereographic and Tomographic Particle Image Velocimetry). The research activities focus on both advancement/development of current/new flow diagnostics techniques, and on the experimental investigation of vortical features, heat transport and mixing in complex flows. The experimental activities are prevalently targeted to aerospace propulsion-related aspects such as swirling flows and turbomachinery cooling.
At the present time, there are two PhD students (Marco Raiola and Carlos Sanmiguel Vila) working within the research group.
A list with our recent publications can be found below, together with a list of our collaborations.

IR Thermography
Owing to methodologies developed by the computer vision community, we developed methods for IR camera calibration and 3D image reconstruction (Ianiro and Cardone, 2010; Cardone et al, 2012) which is fundamental when performing IR temperature measurements on complex models such as re-entry geometries in hypersonic wind tunnels. This technique was successfully applied in hypersonic plasma wind tunnel tests (see Fig. 1). We have also developed a steady-state novel technique to measure convective heat transfer on surfaces on which uniform external heating input cannot be provided (Carlomagno et al, 2011).
Current research is devoted also to the development of new heat transfer sensors for the measurement of time resolved heat transfer features. This research is done in collaboration with University of Naples Federico II.

Hypersonic Thermography :-(
Fig.1 Visualization of shock waves and temperature measurements on a wing leading edge in hypersonic flow (Di Clemente et al. 2013)

Tomographic Particle Image Velocimetry
The increasing need of 3D data of complex turbulent flows pushed towards the development of 3D3C measurement techniques. Among the others, Tomographic PIV has stood out in the last years as the most promising PIV-based technique to reach this task. We have the availability of one of the few complete non-commercial Tomographic PIV codes in the world, and we produced as outcome several journal contributions on the improvement and implementation of the technique (Discetti and Astarita, 2012a; Discetti and Astarita 2012b; Discetti et al, 2013a; Discetti et al, 2013b; Novara et al, 2013), as well as the application of the technique to complex turbulent flows (Discetti, PhD thesis, 2013; Ceglia et al 2013).
Current research efforts are directed towards the improvement of the measurements spatial resolution for the application to turbulent flows. These activities are carried out in collaboration with Arizona State University, Delft University of Technology and University of Naples Federico II.

POD Tomo :-(
Fig.2 POD modes extracted from Tomographic PIV data of a free (a) and confined swirling injector (Ceglia et al 2013)

Impingement Heat Transfer
Impinging jets are very popular in many industrial applications such as turbine blades cooling due to their high heat transfer rate. We contributed several papers on using Tomographic PIV and IR Thermography for flow field (Fig. 3) and heat transfer measurements in impinging jets (Ianiro and Cardone, 2012; Violato et al, 2012; Imbriale et al, 2014).
Current research is devoted and to the design of synthetic jets and fractal turbulence generators for heat transfer enhancement and to the validation of RANS models for swirling impinging jets. These researches are done in collaboration with Delft University of Technology, University of Malaga and University of Naples Federico II.

Impinging :-(
Fig. 3 Left:visualization of the instantaneous flow field in a circular impinging jet (Violato et al. 2012). Rigth: leading edge impingement cooling (Imbriale et al 2014)

Swirl flows
Swirling jets are widely used in gas turbine combustors to generate an inner recirculation region near the jet nozzle to promote the flame stabilization. Moreover, swirling flows have demonstrated their capability in reducing the pollutants emissions and improving the control of the combustion processes. We contributed some of the first 3D field measurements of swirling jets, unrevealing their instantaneous flow features (Ianiro, PhD Thesis, 2012; Ceglia et al, 2013). We are currently interested in the vortical dynamics of the Precessing Vortex Core. This research is done in collaboration with Delft University of Technology and University of Naples Federico II.

Swirl :-(
Fig. 4 Instantaneous velocity field of a free (left) and confined (right) swirling jet (Ceglia et al. 2013).

Flapping wings
Micro Unmanned Air Vehicles (UAVs) are capturing an increasing interest in the aeronautic industry for many purposes. The relatively low Reynolds number and the need to work in hovering conditions prevents the use of fixed wing configurations. Nature provides a brilliant solution to this problem in the flapping wings of birds and insects. The task of the research project is to improve the understanding of the complex unsteady aerodynamics of flapping wings. As a first step, we are performing tomographic PIV experiments to improve our prediction capabilities of the flow dynamics of flapping wings at low Reynolds numbers.
Marco Raiola is working on this project as part of his PhD studies. This research is done as a joint project in collaboration with the Computational Fluids Mechanics Lab.

Recent journal publications
  1. On PIV random error minimization with optimal POD-based low order reconstruction
    Raiola M, Discetti S, Ianiro A Experiments in Fluids, 56:75 (2015) [link]
  2. Convergence enhancement of single-pixel PIV with symmetric double correlation
    Avallone F, Discetti S, Astarita T, Cardone G Experiments in Fluids, 56:71 (2015) [link]
  3. Thermo-fluid-dynamics of submerged jets impinging at short nozzle-to-plate distance: a review
    Carlomagno GM, Ianiro A Experimental Thermal and Fluid Science, 58:15-35 (2014) [link]
  4. Heat transfer enhancement of impinging jets with fractal-generated turbulence
    Cafiero G, Discetti S, Astarita T International Journal of heat and mass transfer, 75:173-183 (2014) [link]
  5. Time and phase average heat transfer in single and twin circular synthetic impinging air jets
    Greco CS, Ianiro A, Cardone G International Journal of heat and mass transfer, 73:776-788 (2014) [link]
  6. On the three-dimensional precessing jet flow past a sudden expansion
    Cafiero G, Ceglia G, Discetti S, Ianiro A, Astarita T, Cardone G. Experimental in Fluids, 55:1677 (2014) [link]
  7. Three-dimensional organization of the flow structure in a non-reactive model aero engine lean burn injection system
    Ceglia G, Discetti S, Ianiro A, Michaelis D, Astarita T, Cardone G. Experimental Thermal and Fluid Science, 52:164-173 (2014) [link]
  8. Convective heat transfer by a row of jets impinging on a concave surface
    Imbriale M, Ianiro A, Meola C, Cardone G. International Journal of Thermal Sciences 75:153-163, (2014) [link]
  9. PIV measurements of anisotropy and inhomogeneity in decaying fractal generated turbulence
    Discetti S, Ziskin IB, Astarita T, Adrian RJ, Prestridge K. Fluid Dynamics Research, 45,061401 (2013) [link]
  10. On a novel low cost high accuracy experimental setup for tomographic particle image velocimetry
    Discetti S, Ianiro A, Astarita T, Cardone G. Measurement Science and Technology, 24,075032 (2013) [link]
  11. Hypersonic test analysis by means of aerothermal coupling methodology and infrared thermography
    Clemente MD, Rufolo G, Ianiro A, Astarita T, Cardone G. AIAA Journal, 51:1755-1769 (2013) [link]
  12. On the near field of single and twin circular synthetic air jets
    Greco CS, Ianiro A, Astarita T, Cardone G. International Journal of Heat and Fluid Flow, in press (2013) [link]
  13. Adaptive interrogation for 3D-PIV
    Novara M, Ianiro A, Scarano F. Measurement Science and Technology, 24,024012 (2013) [link]
  14. Spatial Filtering Improved Tomographic PIV
    Discetti S, Natale A, Astarita T. Experiments in Fluids, 54:1505-1517 (2013) [link]
Collaborations
  1. Aerodynamics Group, TU Delft.
  2. KTH, Department of Mechanics
  3. CIRA
  4. Industrial Engineering Department, University of Naples Federico II
  5. Laboratory for Energetic Flow and Turbulence, Arizona State University.