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Turbulent flow past a radiator contributes to noise emission when interacting with a downstream cooling fan. This study examines turbulent flow characteristics downstream of a radiator, focusing on turbulence production, dissipation, non-homogeneity, and anisotropy. We assess turbulence models based on isotropy and homogeneity for noise prediction in real applications. Results show significant non-homogeneity due to the radiator grid's wakes, extending downstream to a region where the fan would be located. Flow in this region trends toward isotropy, especially when considering a downstream circularly-holed wood panel mimicking the flow contraction caused by a fan casing. The radiator core's fins and louvers break down vortical structures more than generating large eddies, as reported in studies involving heat exchangers with larger gaps between cooling pipes. The von Kármán turbulence model approximates the experimental spectrum, but caution is needed with rapid flow acceleration. This investigation enhances our understanding of turbulence characteristics in the vicinity of radiators with implications for noise spectrum prediction and modeling in such systems. • Automotive Noise Emissions: Radiators alter the noise emitted by cooling fans. • Turbulence Analysis: Flow past a radiator is characterized in realistic conditions. • Evaluation of Turbulence Models: For noise prediction in automotive cooling systems. • Experimental Technique: Stereo PIV to study the airflow downstream of radiators. [ABSTRACT FROM AUTHOR]

[Display omitted] • Multiphase flow experiments require the proper control of the particle concentration. • The injected mass has to be corrected by velocity and particle size. • Nonlinear effects are due to the polydispersion of the powder sample. Multiphase flow experiments allow the understanding of complex interaction mechanisms between particles and fluid structures under controlled conditions. In standard test rigs, the airflow is mixed with precise dust amount continuously, and accurate knowledge of the aerosol amount injected is mandatory to achieve reliable measurements and results. This work proposes the experimental procedure for calibrating an aerosol dosing and injection system. The purpose-built calibration system layout is explained in detail. To give a general perspective of the procedure, four test powders commonly used in multiphase flow tests have been used: Alumina, Silicon Carbide, and two grades of standard soil named Arizona Road Dust. Methodologies and criticisms are reviewed and assessed, and the final results are given in the form of calibration curves of the feeding system. Since the proposed correction is based on powder and flow characteristics, the proposed methodology can be applied to several cases and conditions. [ABSTRACT FROM AUTHOR]

• The adiabatic wall temperature of the supersonic nozzle for moist air flow with condensation are measured with IR camera. • Initial moisture content varied in the range of 0.5–20.2 g/(kg. dry air) and initial relative humidity in the range 20–90%. • Regimes with subcritical and supercritical heat additions are implemented. • It is shown that behind the zone of spontaneous condensation, adiabatic wall temperature depends on the initial moisture content. • The local temperature recovery factor decreases with an increase in the initial moisture content. The expansion of moist air in supersonic nozzles is accompanied by spontaneous condensation of water vapor due to a sharp decrease in flow temperature and pressure. However, in the near-wall boundary layer due to the viscous dissipation, moist air temperature decreases slightly in comparison with initial one. This leads to the fact that the vapor remains overheated in the near-wall region and condensation does not spread to its entire depth. Droplets formed in the core flow as a result of condensation can penetrate into the near-wall region due to turbulent diffusion and evaporate due to higher temperature in the near-wall region. This process causes cooling of the near-wall gas layers and, consequently, a decrease in the adiabatic wall temperature. A decrease in the adiabatic wall temperature relative to the stagnation temperature leads to a decrease in aerodynamic heating and, consequently, in the heat flux from the gas to the body. In this paper, measurements of the adiabatic temperature of the supersonic nozzle wall for moist air flow with condensation are presented. Temperature measurements were made using an infrared thermal imager. Initial moisture content varied in the range of 1.5–20.2 g/(kg. dry air) and initial relative humidity in the range 20–90%. It is shown that in the region behind the zone of spontaneous condensation ("condensation shock"), adiabatic wall temperature depends on the initial moisture content and can be either greater or less than the value of a single-phase (dry air) flow with identical initial flow parameters. Estimates of the flow parameters behind the condensation region are obtained using one-dimensional diabatic flow equations and experimental static pressure distributions along the nozzle length. The correlation between the initial moisture content, the average droplet size and the temperature recovery factor is shown. [ABSTRACT FROM AUTHOR]