Verification of flow velocity measurements using micrometer-order thermometers

In flow velocity measurements, resolution, miniaturization, and accuracy of measuring devices are important issues because the measuring devices significantly affect the flow in the micro-space, sonic flow, and turbulent flow. We studied recovery temperature anemometry (RTA) using micrometer-order thermometers and evaluated its validity in two velocity ranges (40–90 and 315–420 m/s) by conducting two experiments and a numerical simulation. The results confirmed that the difference between the reference velocity and RTA was within 5% in the velocity range 60–90 m/s for both the thermocouple and platinum thermometer given the same recovery temperature coefficient of 0.83. It is a valuable finding that velocity measurement by RTA is independent of the type of thermometer used. This suggests that the accuracy of about 5% can be guaranteed even without calibration by giving the recovery temperature coefficient according to the thermometer geometry, which is an excellent advantage not found in other anemometers. Furthermore, the supersonic flow measured using RTA agrees well with the simulation results and theoretical trends. Our findings ensure that the micrometer-order point measurement of flow velocity, which is difficult with existing anemometers, using RTA is possible over a wide range of flow velocities.

Time Dependent Effect of flow properties on addition of heat to the air flow at Compressible Subsonic Speeds

Heat addition process is a governing phenomenon in turbojet and ramjet burners, where heat is added to the flow during the fuel-air combustion process. In the present work, an analytical study has been performed to investigate the effect of heat addition on the basic flow properties based on compressible Rayleigh flow model between the subsonic and sonic flow regime. The unsteady nature of flow properties in these regimes have been evaluated analytically by adding heat through the walls of a constant area, frictionless duct in which air flow occurs over different periods of time. Sudden variation of temperature, pressure, velocity and kinetic energy of the flow were found at flow Mach number M = 0.94. Flow velocity and kinetic energy increases until the flow approaches M = 0.94, afterwards there is a rapid increase in the flow velocity and kinetic energy until it reaches sonic conditions. Conversely, pressure decreased till the flow reaches M = 0.94, there after a sudden drop was observed. Flow enthalpy increased initially, reached maximum at flow M = 0.845 and then reduced till sonic conditions. Based on the observations, it has been concluded that the heat energy contributed to increase the kinetic energy thereby reducing the temperature of the flow.

Numerical Study of Bleed Slot Flow Characteristics Using Magneto-Aerodynamics

A numerical study into magneto-aerodynamic bleed control systems has been undertaken with the intent of improving the shock swallowing ability of high speed engine intakes. Past research has shown that bleed slots effectively remove sufficient mass flow of air from the system to permit shocks to be swallowed. A magnetic field's influence on a charged boundary layer creates a possibility of sealing a bleed slot when not needed. 2D bleed slots were modeled using structured grids for use with the FLUENT CFD solver. User defined functions were written to simulate charge generation and magnetic field forces. Solutions revealed that bleed slot angles, free stream Mach numbers, pressure ratios, boundary layer displacement thickness, field strength and field position all affect how the system performs. Results have shown that a properly positioned magnetic field can reduce sonic flow coefficients up to 88%, thus justifying further research and investment in wind tunnel experiments.

Numerical Study of Bleed Slot Flow Characteristics Using Magneto-Aerodynamics

A numerical study into magneto-aerodynamic bleed control systems has been undertaken with the intent of improving the shock swallowing ability of high speed engine intakes. Past research has shown that bleed slots effectively remove sufficient mass flow of air from the system to permit shocks to be swallowed. A magnetic field's influence on a charged boundary layer creates a possibility of sealing a bleed slot when not needed. 2D bleed slots were modeled using structured grids for use with the FLUENT CFD solver. User defined functions were written to simulate charge generation and magnetic field forces. Solutions revealed that bleed slot angles, free stream Mach numbers, pressure ratios, boundary layer displacement thickness, field strength and field position all affect how the system performs. Results have shown that a properly positioned magnetic field can reduce sonic flow coefficients up to 88%, thus justifying further research and investment in wind tunnel experiments.

INTENSIFYING THE SONIC FLOW IN THE AUSCULTATION DEVICE

The design of an auscultation device with a mechanical sonic flow densifier is presented. The relationship associating the sonic flow amplification level with the auscultation device dimensions is obtained.

The «Chateau of the Loire Valley» piano fresco as a representation of the artistic thinking of Lesia Dychko

The purpose of this represented scientific article is to reveal the specificity of piano thinking of L. Dychko as exemplified in the «Chateau of the Loire Valley» piano fresco. Methods. The methodological background of the study includes the integration of general scientific (historical, system-related, dialectic, culturological, comparative) and special artistic, in particular, music study methods and approaches of the scientific study. The application of the series of special methods of the music study research, characteristic to the historical, theoretical and performance musicology promoted the solution of the problems brought up in the article. Scintific novelty. The scintific novelty of the undertaken study is the revealing of the conceptual bases and intonational-stylistic specificity of the «Chаteau of the Loire Valley» piano fresco as the representation of the universality of L. Dychko’s creative thinking. Conclusion. The article reveals the form-forming and textural principles of the music mirroring of the masterpieces of French architecture in the text of the «Chаteau of the Loire Valley» piano cycle. The performed analysis enabled the distinguishing of L. Dychko’s piano piece as a model of the interspecific artistic communication and a manifestation of the artistic dialogue within «music - architecture» system, which is revealed on the graphically-associational, intonational and semantic, structural, texture and stylistic levels. The article proves that the «Chаteau of the Loire Valley» fresco of Lesia Dychko is distinguished by the immensity of the artist's intention, concert performance and stylistic direction and the high level of the pianistic technique, which is evidenced by the diversity of the piano texture, wide register coverage of the fingerboard, the predominance of the elements of octaval-chordal technique, the diversity of masterly performed passages and figured approaches, which are indued with formal and meaningful properties and acquire the value of the stylistic and graphically-semantic factors. There has been proved in the work the composer’s appeal to the music thesaurus of contemporary pianism, the established in the piano practice texture and expressive means and general types of movements, as well as the individualized performance approaches, endued in the context of the cycle with different functionally-semantic loads (coloristic background, representation of the sonic flow dynamics, graphical and emotional tension, disconcentrated figurative thematic invention, concert-virtuous style).

ACOUSTIC PROTECTION IN DEVICES WITH VACUUM LAYER

Structures using a vacuum layer for acoustic protection are described. The advantages and disadvantages of using the creation of vacuum to establish sonic flow barriers are demonstrated.