scholarly journals Impact Anlysis of Bow Flap on LHA-1 Ship Airwake

2018 ◽  
Vol 179 ◽  
pp. 03007
Author(s):  
Jinling Wang ◽  
Guangwen Jiang ◽  
Jun Shen ◽  
Chujun Hu
Keyword(s):  
Numerical Simulation ◽  
Simulation Method ◽  
Equation Model ◽  
Separation Region ◽  
Operating Environment ◽  
Study Results ◽  
Helicopter Landing ◽  
Hybrid Grid ◽  
Under Construction ◽  
The Impact

The sharp 90°corner of bow found on American Tarawa class general amphibious assault ship LHA-1 will produce large separated region in the airwake over the ship, and the turbulence in the separation region seriously affects the operation safety of the helicopter. In order to reduce the separation in bow region of the LHA-1, and optimize the helicopter operating environment, the numerical simulation method is used to study the influence of the bow flap on the airwake of LHA-1. The study results show that: the ANSYS k-ε two equation model based on the hybrid grid can be used to predict the steady-state characteristics of the ship airwake; the bow flap can improve the flow field downwind of the flap installation position, and the impact range can cover two spots; in headwind, the optimal installation angle of the bow flap is 15°~25°. The research results of this paper can provide modification and improvement reference for the amphibious assault ship in-service and under construction, so as to achieve the purpose of optimizing the ship airwake, thereby improving the safety of helicopter landing process and extending the service life.

scholarly journals Numerical simulation and experimental research of cavitation nozzle based on equation curve

2021 ◽  
Author(s):  
Lifu Wang ◽  
Dongyan Shi ◽  
Zhixun Yang ◽  
Guangliang Li ◽  
Chunlong Ma ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Flow Field ◽  
High Speed ◽  
Quadratic Equation ◽  
Outer Contour ◽  
Study Results ◽  
Fluent Software ◽  
The Impact ◽  
Better Than

Abstract To further investigate and improve the cleaning ability of the cavitation nozzle, this paper proposes a new model that is based on the Helmholtz nozzle and with the quadratic equation curve as the outer contour of the cavitation chamber. First, the numerical simulation of the flow field in the nozzle chamber was conducted using FLUENT software to analyze and compare the impact of the curve parameters and Reynolds number on the cleaning effect. Next, the flow field was captured by a high-speed camera in order to study the cavitation cycle and evolution process. Then, experiments were performed to compare the cleaning effect of the new nozzle with that of the Helmholtz nozzle. The study results demonstrate that effective cavitation does not occur when the diameter of the cavitation chamber is too large. For the new nozzle, with the increase of the Reynolds number, the degree of cavitation in the chamber first increases and then decreases; the cleaning effect is much better than that of a traditional Helmholtz nozzle under the same conditions; the nozzle has the best cleaning effect for the stand-off distance of 300 mm.

Influence of Oriented Perforation Design on Refracture Reorientation: Simulation and Experiment

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Minhui Qi ◽  
Mingzhong Li ◽  
Tiankui Guo ◽  
Chunting Liu ◽  
Song Gao ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Large Scale ◽  
Simulation Models ◽  
Fracture Initiation ◽  
Simulation Method ◽  
Induced Stress ◽  
Study Results ◽  
Simulation Results ◽  
Fracturing Experiments ◽  
The Impact

The oriented perforating is the essential technique to guide the refracture reorientation, but the influence of the oriented perforation design on the refracture steering radius is still unclear. In this paper, the factors influencing the refracture reorientation were studied by simulation models and experiments. The effects of initial fracture, well production, and perforations on the refracture initiation and propagation were analyzed. Three-dimensional finite element models were conducted to quantify the impact of perforation depth, density, and azimuth on the refracture. The large-scale three-axis hydraulic fracturing experiments guided by oriented perforations were also carried out to verify the fracture initiation position and propagation pattern of the simulation results. The research results showed that perforations change the near-wellbore induced stress distribution, thus changing the steering radius of the refracture. According to the simulation results, the oriented perforation design has a significant influence on the perforation guidance effect and refracture characteristics. Five hydraulic fracturing experiments proved the influence of perforating parameters on fracture initiation and morphology, which have a right consistency between the simulation results. This paper presents a numerical simulation method for evaluating the influence of the refracture reorientation characteristics under the consideration of multiple prerefracturing induced-stress and put forward the oriented perforation field design suggestions according to the study results.

Stability Analysis of Side Slope under Normal and Rainfall Conditions

2013 ◽  
Vol 275-277 ◽  
pp. 1383-1388
Author(s):  
Cheng Liang Zhang ◽  
Lei Liu ◽  
Chun Wang
Keyword(s):  
Numerical Simulation ◽  
Simulation Method ◽  
Unstable State ◽  
Electrical Method ◽  
Rainfall Condition ◽  
Long Term Stability ◽  
Side Slope ◽  
Numerical Simulation Method ◽  
The Stability ◽  
The Impact

The paper studied a side slope engineering of highway in K29+450~K29+900 sections by making an on-site survey of landform and geological features of the side slope. By combining drilling, high-density electrical method and numerical simulation method, the depth and range of the sliding surface were determined. The stability of the side slope after an excavation in a normal and a rainfall conditions was analyzed using numerical simulation method, and simulation results show that in the normal condition the safety factor of the side slope is 1.12, and it is 1.05 in the rainfall condition; the distribution of plastic zones is wide, especially in the rainfall condition, the side slope has a large deformation and is in an unstable state. When a program of side slope reinforcement is chosen, the impact under rainfall condition should be considered in order to ensure long-term stability of side slope.

scholarly journals The effect of commitment, leadership and compensation on job satisfaction and performance of government apparatus in West Sulawesi Province

2019 ◽  
Vol 3 (1) ◽  
pp. 1
Author(s):  
Atika Atika ◽  
Basri Modding ◽  
Baharuddin Sammaila ◽  
Hamzah Hafied
Keyword(s):  
Job Satisfaction ◽  
Organizational Performance ◽  
Structural Equation Model ◽  
Structural Equation ◽  
Fundamental Problem ◽  
Equation Model ◽  
Individual Characteristics ◽  
Study Results ◽  
And Performance ◽  
The Impact

<p>The apparatus performance is a fundamental problem affecting the organizational performance of West Sulawesi Province Government. Many factors affect it, both individual characteristics and organizational, especially commitment, leadership, compensation and job satisfaction. This study analyzes the effect of organizational commitment, leadership and compensation on job satisfaction and the impact on apparatus performance. The study was conducted on 358 respondents of Government apparatus in West Sulawesi Province. The data was collected by five point Likert scale and analyzed by Structural Equation Model (SEM). The study results found that commitment and leadership affect on job satisfaction and apparatus performance. While compensation only affects job satisfaction and does not affect on performance apparatus.</p>

Research on Relationship between Weight Filter Function and Stiffness Filter Function

2011 ◽  
Vol 411 ◽  
pp. 580-583
Author(s):  
Zhen Shang ◽  
Yun Kang Sui
Keyword(s):  
Numerical Simulation ◽  
Topology Optimization ◽  
Least Squares Method ◽  
Simulation Method ◽  
Homogenization Method ◽  
Structural Topology Optimization ◽  
Structural Topology ◽  
Filter Function ◽  
The Impact ◽  
The Relationship

Combined with the homogenization method and the least squares method, the filter function with the form of power function is studied in the Independent Continuum Map (ICM) method. Then, the numerical simulation method is used to study the relationship between a weight filter function and a stiffness filter function. Finally, the impact of the filtration function on the efficiency of topology optimization is showed by examples. It is important to further research structural topology optimization.

scholarly journals A PROXY MODEL TO PREDICT WATERFLOODING PERFORMANCE IN CHANNELING DELTAIC SAND RESERVOIR

PETRO ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 30
Author(s):  
Amega Yasutra ◽  
Dedy Irawan ◽  
Frans Ondihon Sitompul
Keyword(s):  
Numerical Simulation ◽  
Reservoir Simulation ◽  
Simulation Method ◽  
Equation Model ◽  
Real Field ◽  
Experiment Data ◽  
Reservoir Performance ◽  
Proxy Model ◽  
Numerical Simulation Method ◽  
Secondary Recovery

<p class="IsiHeading1">In recent days, waterflooding activities carried out as a part of secondary recovery. Before performing waterflooding, engineers have to perform reservoir simulation first to predict reservoir performance in order to waterflood. Generally, reservoir simulation is conducted by using numerical simulation method. Numerical simulation gives precise results although it depens on the availiability, quality, and quantity of reservoir characteristic and injection operation data. In addition, numerical simulation also time-consuming and quite complex to use. Proxy model is kind of machine learning. It’s able to predict performance of waterflooding quickly and easier to use. The result isn’t differ too much with numerical simulation method. Proxy model is an equation model that construct form quite many experiment data. This research is trying to predict performance of normal 5 spot waterflooding in reservoir with channeling deltaic sand sedimentation by using proxy model. The proxy model will be tested on a real field case. The results indicate that proxy model is able, faster, reliable and easy to use to predict waterflooding performance in such type of reservoir.</p>

A Study on the Willingness to Develop Sports Tourism in Taiwan

2018 ◽  
Vol 3 (2) ◽  
pp. 61-66
Author(s):  
Chih-Wei Lin ◽  
Wei-Ming Chen ◽  
Wei Peng Tan ◽  
Su-Shiang Lee ◽  
Wen-Hua Yang
Keyword(s):  
Place Attachment ◽  
Structural Equation ◽  
Negative Impact ◽  
Positive Impact ◽  
Positive Influence ◽  
Equation Model ◽  
Jel Classification ◽  
Study Results ◽  
Sports Tourism ◽  
The Impact

Objective - This study aims to construct a model for the willingness to develop sports tourism, using the factors of place attachment, the impact of sports tourism, attitude and willingness to develop sports tourism. Methodology/Technique - The study gathers data via questionnaires. Following this, purposive sampling is used to distribute the questionnaires and the collected data is analysed using descriptive statistics, confirmatory factor analysis and a structural equation model. Findings - Once the aforementioned analysis is conducted, the following conclusions were drawn. First, the model construction fits well. Second, the factor of place attachment has a significant positive influence on the perceived impact of sports tourism. Both the positive perception of sports tourism and the attitude for developing sports tourism have a positive impact on willingness to develop sports tourism. Contrary to this, negative perceptions of sports tourism have a negative impact on the attitude to develop sports tourism, although it has no significant impact on the willingness to develop sports tourism. Novelty - This study demonstrates that the higher the degree of place attachment associated with the inhabitants of Taiwan, the greater recognition there is of the impact of sports tourism. The most important finding of this study is that this positive impact enhances the attitude and willingness of inhabitants to develop sports tourism. The study also develops some practical strategies based on the study results. Type of Paper: Empirical Keywords: Place Attachment; Willingness; Sports Tourism; Tourism Impact. JEL Classification: Z30, Z39.

The Study of Design and Installation Process for Supersonic Nozzle

2012 ◽  
Vol 569 ◽  
pp. 500-503
Author(s):  
Lian Sheng Wu ◽  
Guang Li Li ◽  
Qi Fu
Keyword(s):  
Numerical Simulation ◽  
Wind Tunnel ◽  
Flow Field ◽  
Test Section ◽  
Supersonic Nozzle ◽  
Simulation Method ◽  
Supersonic Wind Tunnel ◽  
Numerical Simulation Method ◽  
Field Quality ◽  
The Impact

A practical optimal design method of supersonic nozzle is proposed for a supersonic wind tunnel’s design. Design a set of nozzle wall lines with the same nozzle length and different Mach numbers 1.5, 2.0, 2.5. Use numerical simulation method for the verify and analysis of the designed nozzle. Mainly study the impact of the installation gradient between nozzle and test section on flow field quality. This wind tunnel is the subsonic, transonic and supersonic wind tunnel and its test section cross is 0.2 m × 0.2 m .The impact on flow field quality of the test section was studied quantitatively by using the numerical simulation method. The installation gradient index was given. It has some practical value to the construction of supersonic wind tunnel. At present, this study has been applied in construction of the wind tunnel. The gradient of the test section import shall not be greater than 0.5 mm.

Numerical Simulation of Internal Flow Field in Blast Furnace Slag Dry Granulating Device

2019 ◽  
Vol 944 ◽  
pp. 1199-1207
Author(s):  
Rui Yun Wang ◽  
Jin Yu Yin ◽  
Su Ping Cui
Keyword(s):  
Numerical Simulation ◽  
Blast Furnace ◽  
Flow Field ◽  
Blast Furnace Slag ◽  
Internal Flow ◽  
Simulation Method ◽  
Cooling Effectiveness ◽  
Field Uniformity ◽  
The Impact ◽  
Furnace Slag

In this paper, CFD numerical simulation method was adopted to study the internal flow field of experimental dry granulating device of blast furnace slag and to research the impact of equipment structure and wind speed on cooling effectiveness. Main content included the internal flow field uniformity under different blade type and number of inlets. The results showed that the internal flow field in strip-blades device was more uniform than fan-shaped blades device. With the increase of air inlets quantity, the internal flow field in device became more uniform and stable, especially when there were 8 air inlets in the equipment.

Research Method of Aerodynamic Characteristics of Heavy Duty Truck in Crosswind

2014 ◽  
Vol 602-605 ◽  
pp. 689-692
Author(s):  
Zhe Zhang ◽  
Lin Lin Ren ◽  
Jie Li
Keyword(s):  
Numerical Simulation ◽  
Comparative Analysis ◽  
Research Method ◽  
Wind Tunnel Test ◽  
Simulation Method ◽  
Aerodynamic Characteristics ◽  
Heavy Duty ◽  
Aerodynamic Coefficients ◽  
Heavy Duty Truck ◽  
The Impact

The research program of crosswind aerodynamics was formulated with yaw model test of the relative motion principle for a domestic heavy duty truck. This approach was applied separately wind tunnel test and numerical simulation, to obtain six aerodynamic coefficients of the corresponding heavy duty truck model, and the numerical simulation method was proved to be true by comparative analysis. The conclusions of aerodynamic characteristics got from simulation could provide a useful reference to reduce the impact on crosswind handling stability and the fuel consumption of the heavy duty truck.

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