An experimental study on boundary layer transition detection over a pitching supercritical airfoil using hot-film sensors

Tabrizian, Arshia; Tatar, Massoud; Masdari, Mehran; Eivazi, Hamidreza; Seddighi, Mehdi

doi:10.1016/j.ijheatfluidflow.2020.108743

Cited by 4 publications

(3 citation statements)

References 40 publications

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“…In wind tunnel tests, there are many techniques that have been used to detect transition locations, such as naphthalene sublimation [12], infrared thermography [13], temperaturesensitive paint [14], shear-sensitive liquid crystals [15], hot-film sensors [16], and oil film interferometry [17]. Vavra et al [18] utilized naphthalene sublimation, infrared thermography, and oil film interferometry to detect the transition location of the boundary layer of a…”

Section: Introductionmentioning

confidence: 99%

Investigation on Transition Characteristics of a Modified RAE5243 Airfoil

Liu,

Wang,

Zhang

et al. 2024

Energies

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The transition characteristics of a modified RAE5243 airfoil were investigated using a wind tunnel test and numerical simulations. Transition detection is of great significance for the assessment of drag reduction. In wind tunnel tests, transition location can be detected by infrared thermography. However, in subsonic and transonic wind tunnel tests, the temperature difference between the laminar flow region and turbulent flow region is small. Moreover, the test models are usually made of metals, which make the transition location hard to identify. Combined with infrared thermography, a carbon nanotube heating coating powered by electricity was used to detect the transition location of a modified RAE5243 airfoil wing. The effects of heating power, angle of attack (AOA), and Mach number were studied. The results show that heating power has no impact on transition location. As the AOA increases, the transition location moves forward. With an increase in Mach number, the transition location moves forward first and then backward, and it reaches its most forward point at Ma = 0.75. The results of our numerical simulations indicate that, at Ma≥ 0.75, a shock wave appears on the wing, and the transition is closely related to the shock wave rather than the adverse pressure gradient.

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Section: Introductionmentioning

confidence: 99%

Investigation on Transition Characteristics of a Modified RAE5243 Airfoil

Liu,

Wang,

Zhang

et al. 2024

Energies

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“…More robust, these sensors can be flush mounted on the surface ([4], [5]) but the measured heat loss is a combination of conduction in the wall and forced convection with the flow. Since they are bot robust and non-invasive (flush-mounted), hot-film probes are widely used for measuring the wall shear stress on models ([6]- [8]).…”

Section: Introductionmentioning

confidence: 99%

Flight-Testing of a MEMS Wall Shear Stress Thermal Sensor on a Microlight Aircraft

Ghouila-Houri,

Arnoult,

Mazzamurro

et al. 2023

2023 Ieee Sensors

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This paper reports the realization of thermal MEMS (Micro Electro-Mechanical Systems) sensors designed for wall shear stress measurement during real flight on a microlight aircraft. Based on constant temperature anemometry and calorimetric principle, the micro-sensors measure the viscous shear stress occurring at the wall of a structure interacting with a fluid flow and detect the flow direction. A proper packaging was realized for ensuring a flush but robust integration of the devices on a pod fixed on a microlight aircraft. Real flight-testing demonstrated the ability of the micro-sensors to realize aerodynamic measurements up to 250 km/h on the microlight aircraft.

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“…It is a fact that through the take-off or landing phases of flight, the pilot must open high lift devices, but the fundamental understanding of boundary layer state over the baseline supercritical airfoil is necessary before getting into the multi-airfoil geometry to have a criterion for comparison. In our earlier study, 18 the transition was investigated over a pitching airfoil using hot-film measurements. Though, the main aims of the present work are as follows: ðiÞ To assess the level of confidence of the results for identifying the transition point obtained from the pressure coefficient compared with the hot-film measurements, ðiiÞ To investigate the applicability of a timefrequency approach for scrutinizing the spectral content and development of the transitional boundary layer including the LSB shedding and the turbulence nature from the hot-film signals and (iiiÞ To evaluate the predictability of two numerical models.…”

Section: Introductionmentioning

confidence: 99%

Investigation of laminar separation bubble over a supercritical airfoil in an incompressible flow

Tatar

Masdari

Tahani

2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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Supercritical airfoils have an unknown behavior at incompressible flow regime and Reynolds numbers lower than those related to their design point at transonic condition. In this work, boundary layer transition is studied over a supercritical airfoil by means of hot-film and pressure measurements completed with numerical simulations. The experiments are performed at chord-based Reynolds number of [Formula: see text]and Mach number of [Formula: see text] at different angles of attack. Hot-film measurement over the upper surface of the supercritical airfoil is carried out and the transition points are computed using the standard deviation of the signals. The upper surface pressure is also recorded and a peak in its second derivative is presented as the transition point generated by the laminar separation bubble mechanism. Moreover, an appropriate time-frequency analysis is applied to the hot-film signals to get an insight into the spectral content and development of the transitional boundary layer structures. On the other hand, two numerical codes are employed and the transition points obtained from numerical simulations are compared with the experimental outcomes. Results express a rapid change of the bubble position over the upper surface, as the angle of attack is increased to the value of [Formula: see text]. Laminar separation bubble is observed in the surface pressure distribution data and is well identified using its second derivative along the streamwise direction. The spectral characteristics of the boundary layer are satisfactorily explored including the streamwise fluctuations within the laminar flow, intermittent behavior of the transitional zone and the wide range of the spectrum in turbulent flow, thanks to the time-frequency analysis. A promising agreement is observed between the transition points computed by both the numerical and experimental studies and confirms the accuracy of findings achieved by the second derivative of surface pressure data, hot-film measurements and the reliability of the employed numerical transition models for optimization studies.

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An experimental study on boundary layer transition detection over a pitching supercritical airfoil using hot-film sensors

Cited by 4 publications

References 40 publications

Investigation on Transition Characteristics of a Modified RAE5243 Airfoil

Investigation on Transition Characteristics of a Modified RAE5243 Airfoil

Flight-Testing of a MEMS Wall Shear Stress Thermal Sensor on a Microlight Aircraft

Investigation of laminar separation bubble over a supercritical airfoil in an incompressible flow

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