Visualization of the 3-dimensional flow around a model with the aid of a laser knife

A method for visualizing the three-dimensional flow around models of various shapes in a wind tunnel at a Mach number of 5 is described. A laser provides a planar light flux such that any plane through the model can be selectively illuminated. The shape of shock waves and separation regions is then determined by the intensity of light scattered by soot particles in the flow

On features of crystal structure of semiconductor-ferroelectric Ag₃AsS₃

The temperature dependences of the unit cell parameters a(T) and c(T) of Ag₃AsS₃ were measured by the X-ray dilatometry method with high precision within the temperature range 100 to 300 K in the dark mode and under laser irradiation (λ = 532 nm). It was found that the parameter c increases almost linear with decreasing the temperature from 300 down to 100 K for samples in the dark. At the same time, for samples that were exposed during cooling to laser irradiation, the increase of the parameter с by the value ∆c ≈ (0.002…0.003) Å is observed at temperatures Tp = 145…147 K. This leap is typical for systems in which a phase transition of the first order occurs. Furthermore, there were investigated temperature dependences of the integral relative intensity I(T) of main structural maxima of Ag₃AsS₃ both in the dark mode and under laser irradiation. It was established the character of the dependence I(T) for these reflexes was changed significantly by laser irradiation

The practice of child and adolescent psychiatry: a survey of early-career psychiatrists in Japan

<p>Abstract</p> <p>Background</p> <p>Child and adolescent psychiatry (CAP), a subspecialty of psychiatry in Japan, is facing a serious workforce shortage. To resolve this situation, the Japanese government has organized a task force and has been working to increase psychiatrists' clinical skills to improve care for children and adolescents with mental health problems. Using an online questionnaire system, the authors have conducted a survey to investigate the perceptions, experiences, and interests of early-career psychiatrists in CAP.</p> <p>Methods</p> <p>The subjects of this study were 182 psychiatrists in Japan whose individual clinical experiences did not exceed 15 years. The authors of this study created an online questionnaire system and e-mailed the URL and login password to all subjects. Respondents anonymously answered the questions. Most questions required an answer indicating a level of agreement scored on a nine-point scale. Responding to the questionnaire was considered to constitute consent, and all respondents' privacy was carefully protected.</p> <p>Results</p> <p>The mean age and clinical psychiatric experience of the subjects were found to be 33.1 ± 4.5 years and 5.43 ± 3.5 years, respectively. On a nine-point scale (with nine being the highest), experience and interest in CAP measured 3.05 ± 1.9 and 5.34 ± 2.5, respectively; further, these two factors showed significant correlation (r = 0.437, p < 0.0001). The mean score for the early-career psychiatrists' confidence in their ability to diagnose and appropriately treat was notably low, at 3.13 ± 1.9.</p> <p>Conclusion</p> <p>Our results demonstrated that early-career psychiatrists self-evaluated their CAP clinical experience as insufficient, and these clinicians' CAP experiences and interests correlated significantly. Therefore, in order to improve child and adolescent medical care, we need to expose young psychiatrists to sufficient CAP cases and explore the factors that could attract them to this field.</p

Temperature sensitive paint application for investigation of boundary layer transition in short-duration wind tunnels

Application of Temperature Senstive Paint (TSP) technology for investigation of boundary layer transition in short-duration wind tunnels is presented. Investigations were made on sharp and blunted flat plates in UT-1 wind tunnel of TsAGI operated in Ludwieg scheme at Mach numbers 5, 6, and 8 (Reynolds numbers from 5.5 · 106 to 26 · 106). Both natural and induced boundary layer transitions were investigated

Laminar-turbulent flow around a wedge placed on sharp and blunted plates

The flow structure and heat transfer on sharp and blunted plates near a wedge have been studied experimentally at Mach number 6 and two Reynolds numbers corresponding to laminar and transitional boundary layers ahead of the wedge. Similarly to the two-dimensional (2D) flow, the plate's blunting causes a decrease of heat transfer at threedimensional (3D) interference between the boundary layer and the shock wave. However, there is a threshold bluntness value beyond which the influence is negligible. Heat transfer and pressure measurements as well as surface flow visualization have been performed by means of panoramic (global) methods based on the use of luminescent coatings. They have been used in a short duration (pulse) wind tunnel for the first time

Starting of generic inlet with blunted wedges

Bluntness e¨ect of gas-compressing wedges on starting and §ow structure in an air inlet was investigated experimentally. The inlet was of internal compression type with §at walls and rectangular cross section. The experiments were carried out in the wind tunnel UT-1M at Mach numbers M = 5 and 8 and Reynolds numbers Re∞L from 2.8 · 106 to 23 · 106. The §ow characteristics were measured by panoramic optical methods. Data demonstrating in§uence of wedge bluntness radius on the inlet starting were obtained at di¨erent Mach and Reynolds numbers as well as at di¨erent contraction ratios. Ambiguity of the §ow regime in the inlet under certain conditions was found

Influence of leading edge bluntness on hypersonic flow in a generic internal-compression inlet

Flow and heat transfer inside a generic inlet are investigated experimentally. The cross section of the inlet is rectangular. The inlet is installed on a flat plat at a significant distance from the leading edge. The experiments are performed in TsAGI wind tunnel UT-1M working in the Ludwieg tube mode at Mach number M∞ = 5 and Reynolds numbers (based on the plate length L = 320 mm) Re∞L = 23 · 106 and 13 · 106. Steady flow duration is 40 ms. Optical panoramic methods are used for investigation of flow outside and inside the inlet as well. For this purpose, the cowl and one of two compressing wedges are made of a transparent material. Heat flux distribution is measured by thin luminescent Temperature Sensitive Paint (TSP). Surface flow and shear stress visualization is performed by viscous oil containing luminophor particles. The investigation shows that at high contraction ratio of the inlet, an increase of plate or cowl bluntness to some critical value leads to sudden change of the flow structure

Three-dimensional shock-wave/boundary-layer interaction at the presence of entropy layer

An experimental and numerical investigation of a gas flow on a flat plate near a single fin and a fin pair, generating crossings shocks, is performed. The study is focused on the plate bluntness influence on the flow field and the heat transfer in the interaction region. The experiments are carried out in a short duration wind tunnel at Mach numbers M = 5, 6, and 8 and Reynolds numbers Re∞L up to 27·106. Luminescent substances are used for heat flux and pressure distribution measurements and for the surface flow visualization. In addition, the heat flux is measured with thermocouple sensors. For a numerical flow simulation, the three-dimensional (3D) Reynolds-averaged Navier-Stokes (RANS) equations are solved using the q-ω turbulence model. It is found that even a small plate blunting affects heat transfer and pressure distributions significantly. Moreover, in the case of crossing shocks, it can cause a global transformation of the flow structure in the area of the interaction between the shock waves and the boundary layer