scholarly journals A Numerical Study of the Critical Threshold for Landslide Dam Formation Considering Landslide and River Dynamics

2021 ◽  
Vol 9 ◽  
Author(s):  
Wei Liu ◽  
Yu-xiang Hu ◽  
Si-ming He ◽  
Jia-wen Zhou ◽  
Kun-Ting Chen
Keyword(s):  
River Flow ◽  
Numerical Study ◽  
Landslide Dam ◽  
Future Climate Change ◽  
Critical Threshold ◽  
Key Factors ◽  
River Dynamics ◽  
The Difference ◽  
Averaged Model ◽  
Erosive Capacity

Landslide dam formation can be influenced by the erosive capacity of river flow and the dynamic characteristics of the landslide. When the deposition rate of a landslide that reaches a river is higher than the erosion rate of river flow, the landslide can form a dam by blocking the channel. Hence, in this paper, a dimensionless discharge threshold for landslide dam formation considering landslide and river dynamics is established and studied numerically. A two-layer depth-averaged model coupled with an erosion term is presented to simulate river and landslide movements and their interactions. Several numerical cases are simulated to study the influence of landslide and river dynamics on the critical threshold for dam formation by considering some key factors, such as landslide velocity and the angle between the river and landslide transport directions. Through the simulations, three types of landslide intrusion into river can be reflected: a dam forms quickly, a dam forms or does not form close to a critical state, and no dam forms. The results show that these factors together affect the process of dam formation if the difference between the landslide and river discharges is relatively small. All results are helpful to further clarify the formation of such dams for natural hazard prevention under future climate change conditions.

Experimental and Numerical Study on Grinding Temperature during Surface Grinding with Different Cooling Methods

2009 ◽  
Vol 416 ◽  
pp. 514-518 ◽  
Author(s):  
Qing Long An ◽  
Yu Can Fu ◽  
Jiu Hua Xu
Keyword(s):  
Numerical Study ◽  
Specific Energy Consumption ◽  
Ground Surface ◽  
Numerical Results ◽  
Surface Grinding ◽  
Grinding Temperature ◽  
Air Jet ◽  
The Difference ◽  
High Specific Energy ◽  
Cooling Methods

Grinding, characterized by its high specific energy consumption, may generate high grinding zone temperature. These can cause thermal damage to the ground surface and poor surface integrity, especially in the grinding of difficult-to-machine materials. In this paper, experimental and fem study on grinding temperature during surface grinding of Ti-6Al-4V with different cooling methods. A comparison between the experimental and numerical results is made. It is indicated that the difference between experimental and numerical results is below 15% and the numerical results can be considered reliable. Grinding temperature can be more effectively reduced with CPMJ than that with cold air jet and flood cooling method.

Enhancement of Full Coverage Film Cooling Effectiveness with Mixed Injection Holes

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
Mukesh Prakash Mishra ◽  
A K Sahani ◽  
Sunil Chandel ◽  
R K Mishra
Keyword(s):  
Film Cooling ◽  
Numerical Study ◽  
Velocity Ratio ◽  
Perforated Plate ◽  
Combustion Chambers ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Full Coverage ◽  
Upstream Direction ◽  
The Difference

Abstract In the present work numerical study of full coverage film cooling on an adiabatic flat plate is carried out. Cooling performance of three configurations of cylindrical holes is studied with downstream injection, upstream injection and mixed injection. In mixed injection configuration one column of holes inject in downstream direction and the holes in the adjacent column inject in the upstream direction. Numerical simulations are carried out at different velocity ratios and circumferentially averaged value of adiabatic film cooling effectiveness is estimated. Simulation results indicate that the mixed injection configuration has better and more uniform cooling, throughout the perforated plate, than with downstream injection. The difference is greater with increase in the velocity ratio. Configuration with upstream injection gives better cooling than mixed injection at front few rows of cooling holes but it shows poorer performance with downstream injection in the downstream rows of cooling holes. The obtained results from this study can be an invaluable input for highly loaded combustion chambers.

scholarly journals КОРПОРАТИВНА СОЦІАЛЬНА ВІДПОВІДАЛЬНІСТЬ ЯК СТРАТЕГІЧНИЙ ПОКАЗНИК ЛОЯЛЬНОСТІ СПОЖИВАЧІВ У НАЦІОНАЛЬНІЙ ЕКОНОМІЦІ

2019 ◽  
Vol 137 (4) ◽  
pp. 22-28
Author(s):  
Зоя Олегівна Іванова
Keyword(s):  
Corporate Social Responsibility ◽  
Social Responsibility ◽  
Consumer Satisfaction ◽  
Key Factors ◽  
Loyal Customer ◽  
Company Reputation ◽  
Performance Enhance ◽  
The Difference ◽  
Sense Of Satisfaction ◽  
Corporate Social

The article provides insights into the concept of corporate social responsibility. The key factors and incentives that encourage entrepreneurs to undertake activities to enhance the level of corporate social responsibility have been identified. The study discusses the key advantages of corporate social responsibility which contribute to the increase in financial performance, enhance company reputation and consumer loyalty, increase sales, reduce staff turnover and foster motivation in the workplace. The relevance of the research is underpinned by the need to substantiate the following aspects: a loyal customer is a consistent source of revenue over the years, based on the customer’s priority choice of a certain company and its affection to a brand; loyalty is an indicator to be statistically processed, thus requiring more active use of mathematical tools to analyze repurchases and the factors that shape buying preferences in favor of a particular company, since there is always profound data analysis on customer loyalty behind the process of building any concept, which effectiveness evaluation is often being questioned. Traditionally, loyalty is understood as consumer satisfaction which is from our perspective a mistake. The difference between satisfaction and loyalty provoked some contradictory interpretations by some of the authors. Given the above, the article explores the existing loyalty definitions which by their nature cover various aspects of the concept. The findings reveal that loyalty can manifest itself at different levels: at the level of the environment; at the level of behavior; at the level of ability; at the level of belief; at the level of values and at the identity level. It has been reasoned that within the context of the national economy, loyalty as a strategic indicator is achieved if a number of conditions are met, i.e.: a consumer should perceive a strong advantage of a certain brand against other competitors; have a desire to repurchase and continue to buy goods of a particular company; the consumer should have a sense of satisfaction with a certain brand. Thus, corporate social responsibility, as an indicator of loyalty, envisages long-term and mutually beneficial relationships between a company and a client which contribute to improving the company's image.

scholarly journals Numerical Study of Fracture Characteristics of Deep Granite Induced by Blast Stress Wave

2021 ◽  
Vol 2021 ◽  
pp. 1-22
Author(s):  
Zheming Zhu ◽  
Weiting Gao ◽  
Duanying Wan ◽  
Meng Wang ◽  
Yun Shu
Keyword(s):  
Shear Failure ◽  
Numerical Study ◽  
Numerical Models ◽  
Rock Fracture ◽  
Initial Pressure ◽  
3D Models ◽  
In Situ Stress ◽  
Vertical Pressure ◽  
The Difference ◽  
Radial Cracks

To study the characteristics of rock fracture in deep underground under blast loads, some numerical models were established in AUTODYN code. Weibull distribution was used to characterize the inhomogeneity of rock, and a linear equation of state was applied to describe the relation of pressure and volume of granite elements. A new stress initialization method based on explicit dynamic calculation was developed to get an accurate stress distribution near the borehole. Two types of in situ stress conditions were considered. The effect of heterogeneous characteristics of material on blast-induced granite fracture was investigated. The difference between 2D models and 3D models was discussed. Based on the numerical results, it can be concluded that the increase of the magnitude of initial pressure can change the mechanism of shear failure near the borehole and suppress radial cracks propagation. When initial lateral pressure is invariable, with initial vertical pressure rising, radial cracks along the acting direction of vertical pressure will be promoted, and radial cracks in other directions will be prevented. Heterogeneous characteristics of material have an obvious influence on the shear failure zones around the borehole.

scholarly journals River flow and sediment transport simulation based on a curvilinear and rectilinear grid modelling approach – a comparison study

2017 ◽  
Vol 17 (5) ◽  
pp. 1325-1334 ◽  
Author(s):  
G. G. Morianou ◽  
N. N. Kourgialas ◽  
G. P. Karatzas ◽  
N. P. Nikolaidis
Keyword(s):  
Sediment Transport ◽  
River Flow ◽  
Morphological Changes ◽  
Field Measurements ◽  
Grid Model ◽  
Curvilinear Grid ◽  
Saint Venant Equations ◽  
Flow And Sediment Transport ◽  
Downstream Section ◽  
The Difference

In the present work, a two-dimensional (2D) hydraulic model was used for the simulation of river flow and sediment transport in the downstream section of the Koiliaris River Basin in Crete, Greece, based on two different structured grids. Specifically, an important goal of the present study was the comparison of a curvilinear grid model with a rectilinear grid model. The MIKE 21C model has been developed to simulate 2D flows and morphological changes in rivers by using either an orthogonal curvilinear grid or a rectilinear grid. The MIKE 21C model comprises two parts: (a) the hydrodynamic part that is based on the Saint-Venant equations and (b) the morphological change part for the simulation of bank erosion and sediment transport. The difference between the curvilinear and the rectilinear grid is that the curvilinear grid lines follow the bank lines of the river, providing a better resolution of the flow near the boundaries. The water depth and sediment results obtained from the simulations for the two different grids were compared with field observations and a series of statistical indicators. It was concluded that the curvilinear grid model results were in better agreement with the field measurements.

Understanding the difference in softness of Australian Soft Rolling Skin wool and conventional Merino wool

2021 ◽  
pp. 004051752110505
Author(s):  
Hao Yu ◽  
Christopher Hurren ◽  
Xin Liu ◽  
Xungai Wang
Keyword(s):  
Fiber Diameter ◽  
Purchasing Decisions ◽  
Key Factors ◽  
Height Difference ◽  
Moisture Regain ◽  
Merino Wool ◽  
Wool Fibers ◽  
Significant Difference ◽  
The Difference ◽  
Wool Industry

Softness is one of the key elements of textile comfort and is one of the main considerations when consumers make purchasing decisions. In the wool industry, softness can reflect the quality and value of wool fibers. There is verifiable difference in subjective softness between Australian Soft Rolling Skin (SRS) wool and conventional Merino (CM) wool, yet the key factors responsible for this difference are not yet well understood. Fiber attributes, such as crimp (curvature), scale morphology, ortho-to-cortex (OtC) ratio and moisture regain, may have a significant influence on softness performance. This study has examined these key factors for both SRS and CM wool and systematically compared the difference in these factors. There was no significant difference in the crimp frequency between these two wools; however, the curvature of SRS wool was lower than that of CM wool within the same fiber diameter ranges (below 14.5 micron, 16.5–18.5 micron). This difference might be caused by the lower OtC ratio for SRS wool (approximately 0.60) than for CM wool (approximately 0.66). The crystallinity of the two wools was similar and not affected by the change in OtC ratio. SRS wool has higher moisture regain than CM wool by approximately 2.5%, which could reduce the stiffness of wool fibers. The surface morphology for SRS wool was also different from that of CM wool. The lower cuticle scale height for SRS wool resulted in its smoother surface than CM wool. This cuticle height difference was present even when they both had similar cuticle scale frequency.

Implementation Features of an Analog Multiplier Based on 5529 Series Structured ASIC

2021 ◽  
Vol 26 (2) ◽  
pp. 154-161
Author(s):  
S.O. Belostotskaya ◽  
◽  
A.A. Lukyanov ◽  
A.S. Roslyakov ◽  
A.N. Semenov ◽  
...  
Keyword(s):  
Development Strategy ◽  
Quadratic Function ◽  
Analog Signal ◽  
Key Factors ◽  
Current Function ◽  
The Development Strategy ◽  
Signal Multiplier ◽  
The Difference ◽  
Ip Blocks ◽  
Function Cell

During the analog signals processing one of the key factors is the reduction of power consumption with high accuracy of signal processing. One way of solving this problem is the implementation of analog IP-blocks. PLLs, AGC, modulators often include the analog signal multipliers. In the paper, the principle of quadratic function cell operation has been described in detail. The analog signal multiplier has been constructed on the basis of the difference of squares arithmetic formula and the considered cell of the quadratic current function. On the basis of the elements of 5529 series structured ASIC, the analog signal multiplier has been simulated and its accuracy has been assessed. The resulting analog complex functional IP-block for signal multiplication is a part of the development strategy for 5529 series structured ASIC library.

Effects of Circumferential Nonuniform Tip Clearance on Flow Field and Performance of a Transonic Turbine

2020 ◽  
Author(s):  
Yun Zheng ◽  
Xiubo Jin ◽  
Hui Yang ◽  
Qingzhe Gao ◽  
Kang Xu
Keyword(s):  
Flow Field ◽  
Numerical Study ◽  
Circumferential Direction ◽  
Tip Clearance ◽  
Computational Domain ◽  
Aerodynamic Efficiency ◽  
Aerodynamic Loss ◽  
The Difference ◽  
And Performance ◽  
Downstream Flow

Abstract The numerical study is performed by means of an in-house CFD code to investigate the effect of circumferential nonuniform tip clearance due to the casing ovalization on flow field and performance of a turbine stage. A method called fast-moving mesh is used to synchronize the non-circular computational domain with the rotation of the rotor row. Four different layouts of the circumferential nonuniform clearance are calculated and evaluated in this paper. The results show that, the circumferential nonuniform clearance could reduce the aerodynamic performance of the turbine. When the circumferential nonuniformity δ reaches 0.4, the aerodynamic efficiency decreases by 0.58 percentage points. Through the analysis of the flow field, it is found that the casing ovalization leads to the difference of the size of the tip clearance in the circumferential direction, and the aerodynamic loss of the position of large tip clearance is greater than that of small tip clearance, which is related to the scale of leakage vortex. In addition, the flow field will become nonuniform in the circumferential direction, especially at the rotor exit, which will adversely affect the downstream flow field.

Numerical Study on Explosion Cutting Process of PMMA Plate and Key Factors Influence on Cutting Performance

2018 ◽  
Author(s):  
Lei Ge ◽  
Yantao Wang ◽  
Huipeng Hu ◽  
Lijun Li ◽  
Yiben Zhang
Keyword(s):  
Numerical Study ◽  
Engineering Application ◽  
Material Model ◽  
Cutting Performance ◽  
Cutting Process ◽  
Transient Pressure ◽  
Key Factors ◽  
Explicit Solver ◽  
The Relationship ◽  
Selection Of

Polymethylmethacrylate (PMMA) has been widely utilized to manufacture the covers of aircraft cockpits, naval vessels, car windows and so on, due to their high transmittance, low density, easy processing formability, high corrosion resistance and excellent mechanical properties. Under special conditions such as ejection lifesaving, the PMMA plate needs to be split precisely by explosion cutting technology. Hence, an accurate numerical simulation of PMMA structures is significantly important in engineering application. This paper aims to study the cutting behavior of PMMA plate numerically and investigate the influencing factors on cutting performance of PMMA plates. First of all, the simulation of explosion cutting process of PMMA plate is carried out by a non-linear explicit solver in LS-DYNA software using the fluid-solid coupling method. Jones-Wilkins-Lee (JWL) equation of state is used to simulate the relationship between the transient pressure and specific volume of explosives during explosion. The material model considering failure behaviors is used in the simulation. Additionally, the influence of explosive dosage as well as explosive type on the cutting performance of PMMA plate is investigated. Furthermore, the effect of PMMA geometry size on cutting performance is discussed. This study contributes to the knowledge for the design of PMMA structures which needs explosion cutting and the selection of explosive dosage and explosive type.

LANFEX: A Field and Modeling Study to Improve Our Understanding and Forecasting of Radiation Fog

2018 ◽  
Vol 99 (10) ◽  
pp. 2061-2077 ◽  
Author(s):  
J. D. Price ◽  
S. Lane ◽  
I. A. Boutle ◽  
D. K. E. Smith ◽  
T. Bergot ◽  
...  
Keyword(s):  
Numerical Study ◽  
Weather Prediction ◽  
Weather Forecast ◽  
Radiation Fog ◽  
Complex Interactions ◽  
Early Results ◽  
Weather Phenomenon ◽  
Forecast Models ◽  
The Difference ◽  
Aerosol Activation

AbstractFog is a high-impact weather phenomenon affecting human activity, including aviation, transport, and health. Its prediction is a longstanding issue for weather forecast models. The success of a forecast depends on complex interactions among various meteorological and topographical parameters; even very small changes in some of these can determine the difference between thick fog and good visibility. This makes prediction of fog one of the most challenging goals for numerical weather prediction. The Local and Nonlocal Fog Experiment (LANFEX) is an attempt to improve our understanding of radiation fog formation through a combined field and numerical study. The 18-month field trial was deployed in the United Kingdom with an extensive range of equipment, including some novel measurements (e.g., dew measurement and thermal imaging). In a hilly area we instrumented flux towers in four adjacent valleys to observe the evolution of similar, but crucially different, meteorological conditions at the different sites. We correlated these with the formation and evolution of fog. The results indicate new quantitative insight into the subtle turbulent conditions required for the formation of radiation fog within a stable boundary layer. Modeling studies have also been conducted, concentrating on high-resolution forecast models and research models from 1.5-km to 100-m resolution. Early results show that models with a resolution of around 100 m are capable of reproducing the local-scale variability that can lead to the onset and development of radiation fog, and also have identified deficiencies in aerosol activation, turbulence, and cloud micro- and macrophysics, in model parameterizations.

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