Flight Test of a Resistive Heating Coating for Visualizing Flow Transition

Watkins, Neal; Peak, Sarah M.; Goodman, Kyle Z.; Frederick, Mike; Hulgan, Tom

doi:10.2514/6.2020-3089

Cited by 5 publications

(1 citation statement)

References 14 publications

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“…The existing mature online testing method of aircraft flow field is mainly infrared thermal imaging method [12][13][14], which maintains the quasi-insulation wall by coating the insulating material to obtain the visual boundary layer state. However, this method cannot obtain the magnitude of wall shear stress or pressure quantitatively.…”

Section: Introductionmentioning

confidence: 99%

Flexible skin for measurement of boundary layer state and flight attitude identification on UAV

Pang

Zhao²,

Zhong

et al. 2023

Smart Mater. Struct.

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The wall shear stress and pressure are important for analyzing boundary layer flow and evaluating the aerodynamic performance of the aircraft. In this study, a flexible skin consisting of dual layer hot-film sensors and pressure belts was developed to measure the distribution of wall shear stress and pressure on an unmanned aerial vehicle (UAV) during increase of angle of attack (AOA), tail spin, and decreases of AOA. The sensitivity of the dual layer hot-film sensor is improved by about 150% due to heat conduction reduced. The relative error of pressure belt is less than 1% at 10-65℃. The boundary layer separation and reattachment time, separation AOA and time-shift of the flow field changes in flight conditions are determined. The separated AOA of the left and right wing boundary layers are 26.41° and 17.58° respectively. There is a delay about four seconds between the separation of the boundary layer and the entry of the tail spin, which can provide early warning to prevent abnormal flight conditions such as post stall and tail spin.

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Section: Introductionmentioning

confidence: 99%

Flexible skin for measurement of boundary layer state and flight attitude identification on UAV

Pang

Zhao²,

Zhong

et al. 2023

Smart Mater. Struct.

View full text Add to dashboard Cite

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Design and Fabrication for Dynamic Color-Changing on Curved 3D-Printed Surfaces

Morita,

Sakura,

Aoyama

et al. 2024

Extended Abstracts of the CHI Conference on Human Factors in Computing Systems

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Experimental Characterization of an Unsteady Laminar Separation Bubble on a Pitching Wing

Guerra

Mertens

Little

et al. 2022

Preprint

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The laminar separation bubble (LSB) that forms on the suction side of a modified NACA \(64_3-618\) airfoil at a chord-based Reynolds number of \(Re = 200,000\) is studied using wind tunnel experiments. First, the LSB is characterized over a range of static angles of attack, - in terms of the locations of separation, transition and reattachment - using surface pressure measurements, particle image velocimetry (PIV) and infrared thermography (IT). For the conditions tested, excellent agreement between the techniques is obtained, showing an upstream shift of the bubble with increasing angle of attack. For the study of steady LSBs, the infrared approach is found to be superior, in view of its higher spatial resolution and experimental simplicity. Subsequently, a pitching motion is imposed on the wind tunnel model, with reduced frequencies up to \(k = 0.25\). While surface pressure measurements and PIV are not affected by the change in experimental conditions, the infrared approach is seriously limited by the thermal response of the surface. To overcome this limitation, an extension of the recently proposed differential infrared thermography (DIT) method is considered. With this method, the unsteady behaviour of the LSB can be partially detected. All three experimental techniques indicate a hysteresis in bubble location between the pitch up and pitch down phases of the motion, caused by the effect of the aerodynamic unsteadiness on the adverse pressure gradient. However, the DIT measurements suggest a larger hysteresis, which is again attributed to the thermal response time of the model surface. The experimental results further reveal that the hysteresis in bubble location is larger than that of the circulation of the wing, indicating that the observed bubble hysteresis is not purely due to instantaneous flow conditions, but has an inherent component as well.

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Flight Test of a Resistive Heating Coating for Visualizing Flow Transition

Cited by 5 publications

References 14 publications

Flexible skin for measurement of boundary layer state and flight attitude identification on UAV

Flexible skin for measurement of boundary layer state and flight attitude identification on UAV

Design and Fabrication for Dynamic Color-Changing on Curved 3D-Printed Surfaces

Experimental Characterization of an Unsteady Laminar Separation Bubble on a Pitching Wing

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