scholarly journals Thermal Aeroelastic Characteristics of Inflatable Reentry Vehicle Experiment (IRVE) in Hypersonic Flow

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Jie Wu ◽  
Zhang Zhang ◽  
Anping Hou ◽  
Xiaopeng Xue ◽  
Xu Cao
Keyword(s):  
Hypersonic Flow ◽  
Large Scale ◽  
Heat Dissipation ◽  
Local Heating ◽  
Great Influence ◽  
Surface Friction ◽  
Coupling Model ◽  
Flexible Structure ◽  
Reentry Vehicle ◽  
Large Scale Vortex

The inflatable reentry vehicle provides a new technical way in aerospace entry, descent, and landing. The structural failure of inflatable reentry vehicle experiment caused by thermal aeroelastic effect is serious, which needs to be further studied. A traditional numerical method about flexible vehicles separates the aeroheating and aeroelastic problems, resulting in poor matching with the actual test. In this paper, a thermal-fluid-solid coupling model considering inflation gas effect was established, which associates the aeroheating and aeroelastic modules and adopts the LES to improve the depicting ability of hypersonic flow. The model was used to solve the thermal aeroelastic characteristics under extreme aeroheating load. From aeroheating results, the large-scale vortex on windward generated by the interaction of the shock layer and boundary layer has great influence on aeroheating due to the heat dissipation, and the skin deformation also increases the surface friction and local heating near depressions. From aeroelastic analysis, the flexible structure performs violent forced vibration induced by the unsteady large-scale vortex on windward, and the aeroheating effect will significantly increase the thermal stress and natural vibration properties. The thermal-fluid-solid coupling method for the flexible structure proposed in this paper provides a reasonable reference for engineering.

ON IMPACT OF LARGE-SCALE VORTEX STRUCTURES ON FLAME SHAPE IN A SWIRLING JET FLOW

2018 ◽  
Vol 11 (2) ◽  
pp. 31-39
Author(s):  
L. М. Chikishev ◽  
◽  
V. М. Dulin ◽  
A. S. Lobasov ◽  
D. М. Markovich ◽  
...  
Keyword(s):  
Large Scale ◽  
Jet Flow ◽  
Vortex Structures ◽  
Swirling Jet ◽  
Large Scale Vortex ◽  
Flame Shape

Unsteady Three-Dimensional Analysis of Inlet Distortion in a Transonic Fan

2006 ◽  
Author(s):  
Peng Sun ◽  
Guotal Feng
Keyword(s):  
Shock Wave ◽  
Total Pressure ◽  
Large Scale ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Inlet Distortion ◽  
Flow Loss ◽  
Large Scale Vortex ◽  
Total Temperature ◽  
Transonic Fan

A time-accurate three-dimensional Navier-Stokes solver of the unsteady flow field in a transonic fan was carried out using "Fluent-parallel" in a parallel supercomputer. The numerical simulation focused on a transonic fan with inlet square wave total pressure distortion and the analysis of result consisted of three aspects. The first was about inlet parameters redistribution and outlet total temperature distortion induced by inlet total pressure distortion. The pattern and causation of flow loss caused by pressure distortion in rotor were analyzed secondly. It was found that the influence of distortion was different at different radial positions. In hub area, transportation-loss and mixing-loss were the main loss patterns. Distortion not only complicated them but enhanced them. Especially in stator, inlet total pressure distortion induced large-scale vortex, which produced backflow and increased the loss. While in casing area, distortion changed the format of shock wave and increased the shock loss. Finally, the format of shock wave and the hysteresis of rotor to distortion were analyzed in detail.

Dynamic behavior of diffusion flame interacting with a large-scale vortex by laser imaging techniques

2005 ◽  
Vol 30 (1) ◽  
pp. 465-473 ◽  
Author(s):  
Masaharu Komiyama ◽  
Tomoya Fujimura ◽  
Toshimi Takagi ◽  
Shinichi Kinoshita
Keyword(s):  
Dynamic Behavior ◽  
Diffusion Flame ◽  
Large Scale ◽  
Imaging Techniques ◽  
Laser Imaging ◽  
Large Scale Vortex

scholarly journals Effects of mode of exercise recovery on thermoregulatory and cardiovascular responses

2002 ◽  
Vol 93 (6) ◽  
pp. 1918-1924 ◽  
Author(s):  
Robert Carter ◽  
Thad E. Wilson ◽  
Donald E. Watenpaugh ◽  
Michael L. Smith ◽  
Craig G. Crandall
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Heat Dissipation ◽  
Sweat Rate ◽  
Local Heating ◽  
Cardiovascular Responses ◽  
Maximal Heart Rate ◽  
Exercise Recovery ◽  
Active Recovery ◽  
Arterial Blood

To identify the effects of exercise recovery mode on cutaneous vascular conductance (CVC) and sweat rate, eight healthy adults performed two 15-min bouts of upright cycle ergometry at 60% of maximal heart rate followed by either inactive or active (loadless pedaling) recovery. An index of CVC was calculated from the ratio of laser-Doppler flux to mean arterial pressure. CVC was then expressed as a percentage of maximum (%max) as determined from local heating. At 3 min postexercise, CVC was greater during active recovery (chest: 40 ± 3, forearm: 48 ± 3%max) compared with during inactive recovery (chest: 21 ± 2, forearm: 25 ± 4%max); all P < 0.05. Moreover, at the same time point sweat rate was greater during active recovery (chest: 0.47 ± 0.10, forearm: 0.46 ± 0.10 mg · cm−2 · min−1) compared with during inactive recovery (chest: 0.28 ± 0.10, forearm: 0.14 ± 0.20 mg · cm−2 · min−1); all P < 0.05. Mean arterial blood pressure, esophageal temperature, and skin temperature were not different between recovery modes. These data suggest that skin blood flow and sweat rate during recovery from exercise may be modulated by nonthermoregulatory mechanisms and that sustained elevations in skin blood flow and sweat rate during mild active recovery may be important for postexertional heat dissipation.

scholarly journals Growth and decay of a large-scale vortex in a turbulent boundary layer.

1990 ◽  
Vol 56 (524) ◽  
pp. 911-918
Author(s):  
Hideharu MAKITA ◽  
Koji SASSA ◽  
Akiyoshi ITABASHI
Keyword(s):  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Large Scale ◽  
Large Scale Vortex

A volumetrically heated jet: large-eddy structure and entrainment characteristics

1996 ◽  
Vol 325 ◽  
pp. 303-330 ◽  
Author(s):  
G. S. Bhat ◽  
R. Narasimha
Keyword(s):  
Large Scale ◽  
Laser Doppler Anemometry ◽  
Local Heating ◽  
Integral Model ◽  
Volumetric Heating ◽  
Electrically Conducting ◽  
Cloud Development ◽  
Entrainment Process ◽  
Centreline Velocity ◽  
Heat Injection

We report here an experimental study of a round vertical liquid jet that, after achieving a self-preserving state, is subjected to volumetric heating between two diametral stations. The heat injection is achieved by applying a voltage across the stations, the jet fluid having been rendered electrically conducting by the addition of acid. Using laser-induced fluorescence, digital image processing and laser-Doppler anemometry, the flow properties of the jet have been studied in detail. It is found that, with sufficient heating, the jet no longer grows linearly with height, and the decay of both centreline velocity and turbulence intensity is arrested, and may even be reversed just beyond the zone of heat addition; nevertheless the entrainment decreases, which is at variance with the hypotheses often made for modelling it. This behaviour is here attributed to the disruptive influence that, as the present experiments show, the volumetric heating has on the large-scale vortical structures in the jet, which are known to be largely responsible for the engulfment of ambient fluid that is the first step in the entrainment process. It is shown that a new non-dimensional heat release number correlates the observed data on changes in jet width. An integral model that would describe the effect of local heating is proposed, and implications for cloud development in the atmosphere are discussed.

scholarly journals Corporate Leadership Strategy Management Based on Entropy Coupling Algorithm

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Zhaoyang Wu ◽  
James Yong Liao ◽  
Shiyong Wang ◽  
Jiaoyao Ji ◽  
Xiaokui Zhao
Keyword(s):  
Large Scale ◽  
Corporate Strategy ◽  
Market Competition ◽  
Coupling Model ◽  
Strategy Management ◽  
Evaluation Index System ◽  
Economic Downturn ◽  
Corporate Leadership ◽  
Leadership Strategy ◽  
Coupling Algorithm

With the continued economic downturn, coupled with the slowdown of domestic economic development and fierce market competition, the development of small and medium-sized enterprises has become more and more difficult. Because the financial background and operating strength of small and medium-sized enterprises are far inferior to large-scale enterprises, coupled with the influence of global economic integration, many small and medium-sized enterprises have gradually closed down. Therefore, exploring the entropy coupling algorithm is of great significance to the role of corporate leadership strategy management. This paper studies the coupling conditions and coupling process of corporate strategy and business model, builds a new coupling model, and goes deep into the coupling model to study the cooperation mechanism between its internal modules and initially builds the company to break through the two major dilemmas at the same time. This paper uses entropy theory to evaluate corporate leadership strategy, constructs an evaluation index system based on entropy, determines the weight of each index, and calculates the entropy value. This paper uses the alpha coefficient to test the reliability of the questionnaire. The value range of α coefficient is [0, 1], and different values represent different reliability. Large enterprises as a whole are mostly in the highly coupled (41.80%) and moderately coupled (27.34%) stages; medium-sized enterprises as a whole are mostly in the highly coupled (39.50%) and moderately coupled (31.50%) stages; small enterprises as a whole are mostly in the moderately coupled (39.50%) and moderately coupled (40.72%), low coupling (33.20%), and high coupling (25.9%) stages; microenterprises as a whole are mostly in the low coupling (43.70%), moderate coupling (36.41%), and high coupling (30.51%) stages. The results show that the entropy coupling algorithm can improve the deficiencies in the leadership strategy and provide a practical and reliable path for carrying out leadership development projects.

Large-scale vortex motion in the Atmosphere

1951 ◽  
Vol 77 (332) ◽  
pp. 309-310
Author(s):  
E. Knighting
Keyword(s):  
Large Scale ◽  
Vortex Motion ◽  
Large Scale Vortex

scholarly journals Investigation of unsteady combustion of methane-air flame in a model combustion chamber with swirling flow

2021 ◽  
Vol 2119 (1) ◽  
pp. 012015
Author(s):  
A S Lobasov
Keyword(s):  
Combustion Chamber ◽  
Large Scale ◽  
Recirculation Zone ◽  
Swirling Flow ◽  
Heating Temperature ◽  
Combustion Products ◽  
Flow Dynamics ◽  
Unsteady Combustion ◽  
Stereoscopic Piv ◽  
Large Scale Vortex

Abstract The present paper reports on the investigation of unsteady combustion of a methane-air mixture, including combustion at increased pressure in the combustion chamber and increased temperature of mixture heating for a model gas-turbine swirl burner based on a design by Turbomeca. To measure the velocity and OH fluorescence fields in the flows a combination of stereoscopic PIV and acetone PLIF systems is used. In all cases, the flow dynamics is associated with the movement of large-scale vortex structures in the inner and outer mixing layers and the flow structure corresponds to a swirling jet with a central recirculation zone containing combustion products. An increase in the heating temperature of the mixture and pressure in the combustion chamber leads to a periodic partial separation of the flame from the model swirl nozzle. However, the flow of fuel through the central channel will stabilize the flame.

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