Characteristics Of Fan Research Articles

Study on The Response Characteristics of Monopile Offshore Wind Turbines under Non-Gaussian loads in Typhoons

The fan structure is often seriously damaged under typhoon, so the study of the fan structure under typhoon is of great significance for its disaster prevention and mitigation. The actual measurement shows that the typhoon has obvious non-Gaussian characteristics, and the influence mechanism of this characteristic on the fan response characteristics is not clear. Therefore study the response characteristics of fans under non-Gaussian load. First, based on the autoregressive AR model, combined with the Johnson conversion model (JTM); second, the wind load is determined based on the specification; then the wind load. Finally, the response characteristics of 5MW fan are studied by characterizing the numerical cases of non-Gaussian fan with different strength of typhoon. The results show that the non-high characteristics of non-Gaussian wind field and the non-Gaussian characteristics become stronger with the strength of the non-Gaussian characteristics of wind field.

Study on the Influence of Tip Clearance on Working Characteristics of High-Altitude Fan

To study the influence of tip clearance on the working characteristics of high-altitude fans, this paper takes the MIX-140 high-altitude fan as the research object. Five different tip clearance (TC) models are selected. The CFD method is used to analyze the changes in the working characteristics of the fan under different flow rates and TCs in ground and high-altitude environments. The reliability of the numerical method is verified through a fan test bench. The results show that the tip leakage flow caused by the TC will continuously deteriorate the working characteristics of the fan. Under the rated flow rate in the ground environment, for every doubling of the blade’s TC, the static pressure difference will decrease by 5%, the efficiency will decrease by 2%, and the power will decrease by 3%. In a high-altitude environment, the flow rate corresponding to the maximum shaft power point of the fan will continuously increase with an increase in the tip clearance, which will bring about additional energy consumption. For high-altitude fans, the deformation caused by the high-speed rotation of the impeller needs to be taken into account. Undoubtedly, it is advantageous to choose the smallest possible tip clearance value. The results of the analysis and test methods in this paper will provide a basis for designing the tip clearance of high-altitude fans.

Sound quality evaluation of small fan noise by tonal components

As Covod-19 has made online meetings from home offices the norm, the noise from small fans installed in information devices has increasingly become a factor disrupting a comfortable environment. In addition, as global warming accelerates, the use of new small fans called wearable fans has expanded, and the distance between small fans and humans has become even closer. In this study, we investigated whether T-TNR and T-PR, which are two methods for evaluating the tone characteristics of small fans, can be applied to the noise of projectors and wearable fans. We investigated a method for selecting dominant components and searched for a method for determining the harshness threshold using T-TNR and T-TPR.

“Keeping it lowkey”: Exploring the experiences of Korean women fans of women's volleyball

Recently, there has been a significant increase in female audiences and fans at professional sport events in South Korea (hereafter Korea), particularly women's volleyball. This growth in higher viewer ratings and stadium attendance is attributed to elements such as athletes’ sportsmanship and their dynamic athletic performances. However, there is little known about the Korean women's volleyball league's fanbase. Previous studies have focused on the experiences of male and female fans’ interpretations of sport fan characteristics, experiences of female fans, or those of traditionally male-dominant sports such as ice hockey and football. Therefore, this study explores the experiences of self-identified women fans of women's professional volleyball in Korea. We seek to understand how research participants were introduced to volleyball, how they express their fanship, and how they define sport fans. According to the findings, a combination of structural systems in higher education and media streaming during pandemic restrictions has allowed volleyball content to become more accessible to research participants. Furthermore, the study examines how dukjil and fan service play significant roles in maintaining fanship, and the influence of generational characteristics on how women fans perceive and define sport fans.

The Effect of Distance between Jet Fans on Gas Transport, Energy Conservation, and Emission Reduction in Long Highway Tunnels

With the rapid development of the national economy, China’s transportation industry is experiencing accelerated development, and, at the same time, the number of long tunnels is constantly increasing. In order to examine the influence of jet fan spacing on gas transport law during the construction of long highway tunnels, this study used the Baima Highway Tunnel in Sichuan as an engineering prototype and established a numerical tunnel ventilation model based on Fluent numerical simulation software. The gas transport characteristics of jet fans in tunnels at different spacings (200 m, 400 m, 600 m, and 800 m) were studied. The results showed that with the increase in jet fan spacing (200 m, 400 m, 600 m, and 800 m), the gas concentration at the tunnel face showed a trend of decreasing and then increasing. Moreover, by analyzing the gas distribution cloud map and the wind flow line diagram, it was determined that the ventilation system effect was the best when the jet fan spacing was 600 m, which met the requirements of a gas concentration of less than 0.5% at the tunnel face and a minimum wind speed of 0.25 m/s. At the same time, according to the optimal spacing for the optimization of the site ventilation system, it was observed that after the ventilation was stabilized (after 600 s), the minimum value of the gas concentration in the left and right tunnel holes diminished from 0.38% to 0.31% and from 0.41% to 0.31%, with rates of reduction of 18.42% and 24.39%, respectively. This indicated that after optimizing the ventilation system at the tunnel site, the concentration significantly decreased compared with before the optimization. Moreover, when the jet fan spacing was 600 m compared with 200 m and 400 m, the annual energy savings were 1900.8 MW·h and 950.4 MW·h, respectively. The research results clarified the optimal layout parameters of jet fans in the Baima Highway Tunnel, providing a reference for the rational layout of jet fans in long-distance tunnels. In addition, the results of this study provide an important theoretical basis for the gas prevention and safe construction of long highway tunnels. Furthermore, this study contributes to research in energy conservation, emission reduction, and sustainable development of energy in the ventilation process during tunnel construction.

Tectonic controls on the morphometry of alluvial fans in an arid region, northeast Iran

ABSTRACT The morphology of alluvial fans provides valuable information about changes in tectonic, climate, base level, and drainage basin characteristics. This study aims to evaluate the relationship between active tectonics and morphometric characteristics of alluvial fans in the less studied southern region of the Joghatay mountain, northeast Iran. The study area includes 13 alluvial fans and their corresponding catchment basins in a region with semi-arid climate. Morphometric characteristics of alluvial fans and their corresponding drainage basin including fan area, fan slope, sweep angle, fan toe length, fan radius, basin area, basin slope, fan’s width-to-length ratio, asymmetry factor, and basin shape were measured. Our results revealed a negative relationship between the slope of alluvial fans and their corresponding basin area. The weak correlation between the drainage basin area and the fans area may be attributed to the lithology and active tectonics in the study area. The small sweep angle values of the studied alluvial fans can be attributed to the activity of thrust faults and presence of an uplifting anticline that resulted in formation of elongated alluvial fans in our study area. Analysis of the relationship between the morphometric characteristics of the fans and their corresponding basins indicated a negative correlation, which can be attributed to the sediment transport efficiency of the basins.

Evolving fill‐and‐spill patterns across linked early post‐rift depocentres control lobe characteristics: Los Molles Formation, Argentina

ABSTRACTInherited rift topography controls the sediment routing, timing of sand supply, and sedimentary linkage of early post‐rift depocentres. Exhumed examples of early post‐rift turbidite systems are rare and previous studies have examined the evolution of individual depocentres; in contrast, the detailed evolution of early post‐rift turbidite systems across multiple depocentres has never been documented. Current fill‐and‐spill models do not detail the stratigraphic architecture and evolution of sedimentological characteristics of multiple intraslope fans developed across topography, including bed type distributions. Here, the evolution of three intraslope fans that developed across two early post‐rift depocentres is documented along an 18 km long transect in the southern Neuquén Basin, Argentina. The relative chronology of sand supply in depocentres is constrained with new U–Pb ages, and sediment source areas with provenance analysis. The early post‐rift intraslope fans record progradation of the system and progressive sedimentary linkage of post‐rift depocentres, transverse to local syn‐rift structures, with sediment routing subparallel to the cratonic basin margin. The large‐scale stratigraphic architecture of intraslope fans indicates an evolution as a fill‐and‐spill system, with initial confinement through flow stripping and overspill to spillover with erosion and bypass across a transverse topographic high separating the depocentres. Changes in early post‐rift intraslope fan characteristics, including thickness, sandstone content, lobe complex stacking patterns, stratal termination patterns and bed type distribution, record changing confinement through time within a depocentre, and spatially across depocentres. The strong spatial and vertical stratigraphic variability of transitional flow deposits and hybrid event beds reflects enhanced erosion, sediment bypass and flow transformation across transverse relief between the two depocentres during the spillover phase. These findings advance current understanding of early post‐rift turbidite systems and refine fill‐and‐spill models, which will help the prediction of spatial and vertical changes in rock quality and connectivity in subsurface hydrocarbon reservoirs and CO2 storage sites.

Study on noise characteristics of centrifugal fan based on blade loading distribution

Abstract In order to explore the influence of different blade loading distribution on the noise characteristics of centrifugal fan, this paper takes the blade loading distribution of the hub and shroud of the centrifugal fan as the design parameters, and establishes four centrifugal fan models with different blade loading distribution. The aerodynamic noise and radiation noise of the centrifugal fan are calculated by the transient results. The research shows that the noise characteristics of the fan change with the change of the blade loading distribution. The maximum aerodynamic noise is generated at the volute tongue, and the total sound pressure level of the gas along the flow direction shows a downward trend. The area with large vibration displacement on the surface of the volute occurs at the back cover plate of the volute, and the noise sound pressure level radiated outward is also higher. The purpose of noise reduction can be achieved by controlling the blade loading distribution.

Morphological effects of leading-edge sawtooth on the vortex evolution and acoustic characteristic of an ultra-thin centrifugal fan

Serrations on the owl wings' leading edge (LE) are considered one of the critical characteristics leading to their silent flight. Inspired by this, LE sawtooth was innovatively induced on ultra-thin centrifugal fan blades, and the morphological effects of these teeth on the vortex evolution and aeroacoustic characteristics of the fan were studied using large eddy simulation and the Ffowcs Williams–Hawkings analogy. A single-passage model was adopted to finely simulate the flow mechanism between blades with an acceptable scale. Five sawtooth schemes with relative tooth width λ/b from 7.96% to 29.84%, as well as the prototype, were calculated and analyzed. It is found that the optimal λ/b ranges from 8% to 17.05%, which reduces the overall sound pressure level (SPL) by over 1 dB without impacting the blade pressure and efficiency. These sawteeth inhibited the LE separation, shattered the leading-edge vortex (LEV) into small vortices, and consequently weakened the pressure fluctuations on the blades. However, more prominent teeth (λ/b > 23.8%) intensify the interactions between LEV and other passage vortices, changing the dominant pressure pulsations to high frequency, in turn raising the overall SPL. Too small sawteeth are challenging to process on such ultra-thin blades, so the largest sawtooth among the suggested range was considered the optimal scheme (λ/b = 17.05%) and was manufactured to measure. The results show that the SPL of the fan with LE sawtooth is 0.24–0.57 dB lower than that of the prototype under the same flow rates, even though its rotational speed is increased.

Research on structural resonance of large axial fan in power plant

According to the structural characteristics of the axial fan, the causes of equipment resonance are analyzed. Four reference methods are proposed, including strengthen the structural stiffness, change the exciting frequency, weaken the exciting force, and strengthen the damping. The characteristics of the response treatment measures are discussed. Take the two-stage axial-induced draft fan of a 600 MW unit as an example, the axial resonance problem has been dealt with well by improving the support stiffness and reducing the excitation force. The research results and treatment can provide an experience reference for the analysis and treatment of the resonance problem of large axial fans.

The Optimization of the Geometry of the Centrifugal Fan at Different Design Points

The optimization of the geometry of a centrifugal fan is performed at maximum power and high-efficiency design points (DPs) to improve impeller efficiency. Two design variables defining the shape of fan blade are selected for the optimization. The optimal values of the geometry parameters of the impeller blades are identified by employing virtual flow simulations. The results of virtual experiments indicate the influence of the parameters of the blade geometry on its efficiency. With the optimization of impeller blade geometry, the efficiency of the fan is improved with respect to the reference model, as confirmed by comparing the performance curves. Herein, we discuss the results obtained in virtual tests by identifying the influence of DPs on the performance characteristics of centrifugal fans.

Depositional pattern and source-to-sink process of submarine fans in Lingshui and Sanya formations, Baodao Sag, Qiongdongnan Basin, China

The deepwater area is one of the frontiers of oil and gas exploration, with the understanding of distribution and genesis of deepwater reservoirs being crucial for reservoir formation research. Despite Baodao Sag in the Qiongdongnan Basin being proven to be rich in hydrocarbon generation, significant oil and gas fields have yet to be discovered in the ultra-deepwater areas, and the distribution patterns of reservoirs in deep water remain unclear. Taking the southern slope area of the Baodao Sag as an example, the distribution characteristics of submarine fans are studied by employing seismic prediction methods, including seismic reflection structure analysis, seismic facies geometry, seismic attribute analysis, and the source-to-sink theory. The results show distinct characteristics: the fan delta exhibits parallel oblique progradational reflection, the slumping submarine fan displays lenticular reflection, and the submarine fan of the Sanya Formation demonstrates subparallel sheet reflection. The provenance of sediment is traced back to the denudation area of the Songnan low uplift and the Southern Uplift area in the southwest. The sediments were primarily transported through two main incised channel systems in the north and south, ultimately flowing into the southern slope area of the Baodao Sag. The application of seismic sedimentological prediction methods and source-sink theory has laid a solid geological foundation for oil and gas exploration and the analysis of reservoir forming conditions in the deepwater area of the Baodao Sag.

Seismic sedimentology response characteristics of nearshore terminal fan in the suning area of Raoyang Sag, Bohai Bay Basin, NE China

A nearshore terminal fan is a special water system formed in arid environments. The characterisation of its thin-channel sand bodies has long been a challenge restricting oil and gas exploration. This study takes the Suning area of the Raoyang Sag as an example and uses the principles of seismic sedimentology to conduct seismic sedimentary research on the nearshore terminal fan of the first member of the Palaeogene Shahejie Formation (Es1) based on three-dimensional seismic, logging, and core analysis. Seven fourth-order sequences (SQV7) were identified within Es1, deposited by a fluvial river system terminating at the contracting bank of a lake. Prograding terminal fan sedimentary facies on a gentle slope zone were observed in the root mean square seismic attributes after spectral decomposition. We have successfully resolved the sandstone within the studied terminal fan system using a 90° phase conversion of the seismic data and red-green-blue (RGB) fusion of the various seismic attributes. The upper subsegment of the Shahejie Formation developed extensive nearshore terminal fan sedimentation, and the seismic sedimentological response characteristics were mainly channel-like and strip-shaped geomorphic systems deposited on gentle slope zones, indicating distributary channels and distal basin sedimentation. This study enriches our understanding of nearshore fans and provides ideas for predicting favourable sand bodies in this type of sedimentary facies.

Numerical analysis of wind effects on aerodynamic characteristics of a ducted fan

Ducted fans have been extensively used in Unmanned Aerial Vehicles (UAVs) for a variety of missions because of high efficiency, high safety and low noise. Wind, as a kind of typical meteorological condition, brings significant aerodynamic interference to the ducted fan, which seriously threatens flight stability and safety. In this work, the numerical simulation with the Unsteady Reynolds Averaged Navier-Stokes (URANS) method and the sliding mesh technique is performed to evaluate the steady wind effect. The results show that the wind will lead to serious unsteady effects in the flow field, and the thrust fluctuates at the blade passing frequency of 200 Hz. As the wind speed increases, the rotor thrust increases, the duct thrust decreases, and the total thrust changes little. Flow instability may occur when the wind speed exceeds 8 m/s. As the angle of low-speed wind increases, the rotor thrust changes little, the duct thrust increases, and the total thrust increases. In addition, we figure out that cases with the same crosswind ratio are similar in results, and increasing the rotating speed or fan radius is beneficial to performance improvement in wind. The findings are essential to the ducted fan design and UAV flight control design for stable and safe operations in wind conditions.

Analysis of internal flow characteristics of squirrel-cage fan with multi-directional air intake impeller

The separate flow in the inlet region of the squirrel-cage fan, caused by airflow steering, hinders the further improvement of internal flow state and aerodynamic performance. This study proposes a multi-directional air intake design of the impeller to solve this problem. Specifically, a new parameter known as D* is introduced in this study to represent the axial air intake parameter of the impeller. Subsequently, the key parameters of the multi-directional air intake impeller (D*, entrance blade angle, exit blade angle) are optimally designed using an orthogonal experimental and CFD numerical simulation. These results are further validated through experimentation, demonstrating that a well-designed multi-directional air intake impeller can increase the fan's air volume, total pressure, and total efficiency by 27.3%, 12.6%, and 5.2%, respectively. Furthermore, it has been observed that the inclusion of an axial air intake in the impeller diminishes the impact of the entrance blade angle on fan efficiency. When evaluating different-sized models, the influence of the axial dimensionless parameter D* on the fan total efficiency shows a consistent pattern, which is worth noting that the efficiency does not necessarily increase with increasing values of D*, but rather the fan efficiency peaks when D* is approximately 0.5. The analysis of the flow field and entropy generation inside the fan reveal that the design can weaken the separation vortex at the inlet and shift the position of vortex core towards the impeller's leading edge, so as to eclectically enhance the uniformity of the impeller inlet and outlet, ultimately optimizing the aerodynamic characteristics within the fan. This study presents a novel approach to controlling the inlet separation flow of a squirrel-cage fan and provides a reference to elucidate the mechanism of internal flow evolution with the multi-directional air intake impeller.

Aerodynamic noise characteristics of a centrifugal fan in high-altitude environments.

In high-altitude areas, the air is thin and the atmospheric pressure is low, which can affect the performance of centrifugal fans and aerodynamic noise. In this paper, steady and unsteady simulations of a centrifugal fan flow field are performed at altitudes of 0, 1000, 2000, 3000, 4000, and 5000 m, and the Ffowcs Williams-Hawkings equation is used to predict the aerodynamic noise of the fan. The results indicate that the tonal and broadband noise generated by the fan decrease with increasing altitude, and the A-weighted sound pressure level of each frequency band of the fan decreases when the air volume is held fixed. The maximum sound power level Lwmax, sound pressure pulsation interval, and total noise sound pressure level Lp decrease linearly with increasing altitude. For every 1000 m increase in altitude, Lwmax and Lp decrease by 0.45 dB and 1.05 dB respectively. The fan noise characteristics, performance parameters, and human auditory perception are the main factors that affect the establishment of fan noise standards in high-altitude areas.

The influence of Xiaohongshu female bloggers on female values

The social media industry in China is diverse, among which an app with a significant female user base is Xiaohongshu. This article discovers that female users’ values are easily influenced by bloggers through an in-depth analysis of the accounts of three different types of female bloggers on the platform (dress-sharing bloggers, fitness bloggers, and shopping-sharing bloggers) and paying attention to their fan characteristics. This article finds that the values of female users are easily influenced by bloggers. On one hand, these mainstream popular videos can not only influence users’ thoughts but also give them help and motivation. This article investigates the phenomena of Xiaohongshu users across a range of age groups and concludes that Xiaohongshu will significantly alter women’s shopping demand and aesthetics. These images and videos will aid female followers in establishing a proper value if the Xiaohongshu bloggers are able to provide accurate and authentic information. On the other side, material provided by bloggers that is not wholly useful might have a negative impact on women’s values.

The Role of Sports Stars in Shaping Fans' Behavioral Characteristics

Objective: The objective of this study is to investigate the impact of sports stars on the behavioral characteristics of fans. Methodology: This research utilized a mixed-method approach (qualitative-quantitative) conducted in two phases. In the qualitative phase, data were collected through in-depth interviews with experts and active sports fans on social media platforms. In the quantitative phase, a researcher-designed questionnaire was distributed among 186 fans and sports managers using purposive sampling. Data analysis was performed using SPSS and Smart PLS software. Findings: The findings revealed that sports stars have a significant impact on all aspects of fan behavior. The influence of sports stars on citizenship behavior (path coefficient 0.992), emotional behavior (path coefficient 0.909), consumptive behavior (path coefficient 0.446), and normative behavior (path coefficient 0.503) was positive and significant, while their effect on deviant behavior was negative and significant (path coefficient -0.592). Conclusion: The results of this study suggest that sports stars significantly influence fans' behaviors, acting as social role models to enhance positive and responsible behaviors while reducing deviant actions. These findings recommend that sports organizations and managers leverage the influence of sports stars to improve fan engagement and foster loyalty.

Analysis and Testing of Variable Height Operating Characteristics of Super-Pressure Balloon Airbag Fan

A fan is part of the core equipment of a super-pressure balloon altitude control system, and high-performance fans have a significant impact on the altitude control capability and flight safety of super-pressure balloons. This paper proposes a mixed-flow MIX-140 fan for use with super-pressure balloons. Changes in the fan’s operating characteristics at various flight altitudes of a super-pressure balloon were investigated. First, the performance of the fan at ground level was obtained through numerical simulation and compared with measured data of the prototype to verify the accuracy of the simulation analysis. On this basis, the influences of changes in the atmospheric pressure, temperature, and fan speed on fan performance were investigated through numerical simulation. Furthermore, the MIX-140 fan was compared with an existing fan, and the variation of two parameters, namely, the ratio of inflation volume per unit time and the ratio of inflation volume per unit power, were investigated at different altitudes. Finally, the changes in the operating characteristics of the fan under different high-altitude environments were investigated through actual testing. The results reveal that changes in altitude can lead to significant changes in fan performance, and changes in the atmospheric pressure, temperature, and fan speed affect the fan’s working characteristics. Compared with the existing fan, the MIX-140 fan achieves an average increase of 295.8% in the inflation volume per unit of time, and 14.6% in the inflation volume per unit of power at altitudes of 16–20 km. The performance variation characteristics and testing methods of this proposed super-pressure balloon fan can provide a foundation and reference for the design of a super-pressure balloon control system.

Developing A Digital Model As A Literature For Preventing And Overcoming Cyberbullying Among Children And Teenagers K-Pop Fans

This study aimed to develop a digital module for Digital Literacy for children and young people who were KPop fans in Makassar, to prevent cyberbullying. Data showed that that K-Pop fans consisting of children and teenagers in Indonesia were one of the largest Internet users in the world. The high use of the internet was also directly proportional to the cyberbullying that occured to them, not only as victims but also as perpetrators. This was the reason, why this study was important to investigate even though many researches on digital literacy had been carried out, but not many had been found specifically targeting KPop fans, while they were active internet users. This study was development research referring to the 4-D model (Four) that proposed by S. Thiagarajan and Semmel (1974), which consisted of 4 stages of development, namely the stage of defining (Define), Design , Development (Develop), and dissemination (Disseminate), then reduced to a 3-D model which only consisted of 3 stages of development, namely the stage of defining (Define), Design, Development (Develop). The results produced a Digital Literacy Module, which emphasized content on digital skills, consisting of Devices used, Search Engines, social media applications and online conversations and shopping, all of which were adapted to the characteristics of KPop Fans.