Recent developments in the aero-optical effects of high-speed optical apertures: From transonic to high-supersonic flows

Ding, Haolin; Yi, Shihe; Xu, Yao; Zhao, Xianwei

doi:10.1016/j.paerosci.2021.100763

Cited by 26 publications

(10 citation statements)

References 60 publications

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“…The calculated flow field results are shown in Figure 9. Compared with the schlieren images obtained from experiments in the literature [23], as shown in Figure 10, the bow shock wave, expansion shock wave, induced shock wave, and oblique shock wave are basically reproduced. Because there is still some error between the simulation and the experiment, the oblique shock wave is not particularly obvious.…”

Section: High-speed Turbulence Via Lesmentioning

confidence: 73%

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A New Method for Analyzing the Aero-Optical Effects of Hypersonic Vehicles Based on a Microscopic Mechanism

Yang

Liu

et al. 2022

Aerospace

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Aero-optical effects are the key factors that restrict the accuracy of the optical sensors of hypersonic vehicles, and the numerical simulation of aero-optical effects is a powerful tool with which to analyze aero-optical distortion. Most existing research focuses on the simulation analysis of refraction distortion based on the density field at the macro level via the ray-tracing method. In this paper, a method for analyzing aero-optical effects based on the interaction between photons and gas molecules is proposed and can explain the optical distortion and energy dissipation caused by aero-optical effects at the micro level. By establishing a transmission model of photons in turbulence, a simulation method of aero-optical effects based on a microscopic mechanism is designed and breaks through the limitations of a traditional macro method in energy analyses. The optical distortion parameters based on photonics are compared with the physical quantities of traditional aero-optical effects, which verifies the effectiveness of the micro analysis on the macro scale and provides a new idea for studying the microscopic mechanism of aero-optical effects.

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Section: High-speed Turbulence Via Lesmentioning

confidence: 73%

“…Although research on aero-optical effects has made some progress through experiments, research on their microscopic mechanism has stagnated [21][22][23]. At present, research on the mechanism of aero-optical effects mainly focuses on the change in the turbulent density field on the optical path.…”

Section: Introductionmentioning

confidence: 99%

A New Method for Analyzing the Aero-Optical Effects of Hypersonic Vehicles Based on a Microscopic Mechanism

Yang

Liu

et al. 2022

Aerospace

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“…HfO 2 film on the surface of CVD zinc sulfide window and yttrium oxide film on the surface of the sapphire window can delay the saturation of the imaging device and improve the resistance of the optical hood to thermal radiation interference [14]. Window cooling methods mainly include external jet cooling and internal cooling, and the cooling airflow of the external cooling scheme mixes with the airflow within the original boundary layer to form a shear/mixed layer complex flow, which may affect the transmission of target light [15], [16]. Nevertheless, window cooling techniques can effectively improve the aero-optical thermal environment or reduce the window temperature, and are still most effective physical means to suppress the window thermal radiation effects [17], [18].…”

Section: Introductionmentioning

confidence: 99%

Progressive Nonuniformity Correction for Aero-Optical Thermal Radiation Images via Bilateral Filtering and Bézier Surface Fitting

Liu

Xiong

et al. 2023

IEEE Photonics J.

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When a high-speed aircraft flies in the atmosphere, the imaging window is subjected to airflow friction, the kinetic energy of the airflow is converted into thermal energy, which makes the surface temperature of the imaging window rise unevenly, the imaging quality is significantly reduced, called aerooptical thermal radiation effects. The continuously increasing nonuniform thermal radiation bias field is not conducive to the precise identification of the target. To remove the bias field in degraded infrared images, this paper proposes a progressive nonuniformity correction method. First, we establish a progressive thermal radiation effects correction model to estimate the thermal radiation bias field based on bilateral filtering and Bézier surface fitting. Then, to avoid overfitting the bias field, the degree of Bézier surface is reduced progressively during the iterative process. Finally, according to the properties of the heat transfer of the aero-optical thermal radiation effects, a gradient orientation prior is imposed for both the thermal radiation bias field and the latent clear image. experiments on simulated degraded images and real degraded IR images show that our method can reduce the thermal radiation effects residual compared with the current aero-optical thermal radiation effects correction methods. The code will be publicly available upon acceptance.

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“…A study presented in [ 7 ] focused on the measurements of pressure oscillations of a practical core-engine annular combustor during the start up. The study in [ 8 ] showed the dominant role of pressure fluctuation on the aero-optical distortions, which are important for the development of airborne optical systems, i.e., missiles with optical seekers, airborne telescopes, airborne free-space communication systems and airborne laser weapon systems.…”

Section: Introductionmentioning

confidence: 99%

Effect of the Dynamic Response of a Side-Wall Pressure Measurement System on Determining the Pressure Step Signal in a Shock Tube Using a Time-of-Flight Method

Svete

Castro

Kutin

2022

Sensors

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Technological progress demands accurate measurements of rapidly changing pressures. This, in turn, requires the use of dynamically calibrated pressure meters. The shock tube enables the dynamic characterization by applying an almost ideal pressure step change to the pressure sensor under calibration. This paper evaluates the effect of the dynamic response of a side-wall pressure measurement system on the detection of shock wave passage times over the side-wall pressure sensors installed along the shock tube. Furthermore, it evaluates this effect on the reference pressure step signal determined at the end-wall of the driven section using a time-of-flight method. To determine the errors in the detection of the shock front passage times over the centers of the side-wall sensors, a physical model for simulating the dynamic response of the complete measurement chain to the passage of the shock wave was developed. Due to the fact that the use of the physical model requires information about the effective diameter of the pressure sensor, special attention was paid to determining the effective diameter of the side-wall pressure sensors installed along the shock tube. The results show that the relative systematic errors in the pressure step amplitude at the end-wall of the shock tube due to the errors in the detection of the shock front passage times over the side-wall pressure sensors are less than 0.0003%. On the other hand, the systematic errors in the phase lag of the end-wall pressure signal in the calibration frequency range appropriate for high-frequency dynamic pressure applications are up to a few tens of degrees. Since the target phase measurement uncertainty of the pressure sensors used in high-frequency dynamic pressure applications is only a few degrees, the corrections for the systematic errors in the detection of the shock front passage times over the side-wall pressure sensors with the use of the developed physical dynamic model are, therefore, necessary when performing dynamic calibrations of pressure sensors with a shock tube.

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Recent developments in the aero-optical effects of high-speed optical apertures: From transonic to high-supersonic flows

Cited by 26 publications

References 60 publications

A New Method for Analyzing the Aero-Optical Effects of Hypersonic Vehicles Based on a Microscopic Mechanism

A New Method for Analyzing the Aero-Optical Effects of Hypersonic Vehicles Based on a Microscopic Mechanism

Progressive Nonuniformity Correction for Aero-Optical Thermal Radiation Images via Bilateral Filtering and Bézier Surface Fitting

Effect of the Dynamic Response of a Side-Wall Pressure Measurement System on Determining the Pressure Step Signal in a Shock Tube Using a Time-of-Flight Method

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