Artykuły w czasopismach: „Bluff”

1

You, Zuo, and Yi Zhe. "Bluff." Massachusetts Review 63, no. 4 (December 2022): 782. http://dx.doi.org/10.1353/mar.2022.0120.

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Amin, Shahalam M. N., and Robin G. D. Davidson-Arnott. "Toe erosion of glacial till bluffs: Lake Erie south shore." Canadian Journal of Earth Sciences 32, no. 7 (July 1, 1995): 829–37. http://dx.doi.org/10.1139/e95-069.

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Toe erosion and rates of recession of the toe were measured at four sites along a 3.5 km long stretch of shoreline on the south shore of Lake Erie from April to December 1986. The shoreline consists of bluffs ranging from 5 to 12 m in height and developed in overconsolidated till. Toe erosion was measured at peg lines consisting of pins driven horizontally into the face of the bluff at 0.25 m intervals to a height of 1.75 m above the beach, and steel rods driven vertically into the beach with a spacing of 1.5 m. At each site three lines were established and monitored at 1–2 week intervals. Because of record high lake levels, beaches in front of the bluffs were generally <5 m wide, and some erosion was measured on all but three occasions. Recession of the toe during any measurement period was generally 2–6 cm, with the maximum recorded being about 12 cm. Wave action during high-magnitude storms resulted in erosion occurring much higher up the bluff face than for low-magnitude events, but the actual recession of the toe was not substantially greater. A multiple regression model shows that there is a significant relationship between toe recession and several variables that indirectly control wave energy at the bluff toe. However, factors such as beach width and thickness of beach sediment did not have a significant influence on recession rates in this study, likely because the high lake levels resulted in very narrow beaches at all four sites throughout the study period.

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Eguchi, Branco Mateus Murata, and Jacqueline Albino. "BLUFF RETREAT INDUCED BY WAVE ACTION ON A TROPICAL BEACH, IN ESPÍRITO SANTO, BRAZIL." Revista Brasileira de Geofísica 36, no. 4 (December 28, 2018): 1. http://dx.doi.org/10.22564/rbgf.v36i4.959.

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ABSTRACT. Interest in understanding sea bluff erosion along the coasts around the world has grown in recent years, especially when in proximity to urban expansion. To prevent economic, social and environmental losses, it is necessary to understand the factors behind the sea bluff erosion. This study analyzed temporal and spatial changes in wave exposure over 60 years (1948-2008) and the corresponding impacts of these variations on three sea bluffs with similar lithology over 55 years (1953-2008). Erosion distances and annual erosion rates were obtained from aerial and satellite images for the time intervals 1953-1970, 1970-1995 and 1995-2008. Analysis of bluff retreat and wave exposure compared annual wave behavior, extreme wave occurrences and modeled spatial and temporal variations in wave energy to yearly retreat rates obtained from imagery analysis and assessed for each of the three intervals. For the three bluffs, the total erosion distance decreased northward – 51, 43 and 18 m, resulting in recession rates of 0.8, 0.69 and 0.43 m/year, respectively. Overall, annual erosion rates appear to slow down during long periods (63 years) compared to the short-term (8-25 years). The shift in modeled wave energy distribution is mainly in accordance with the longshore variability of erosion rates. However, the relationship between bluff recession and wave energy shows that periods of high energy are not necessarily related to intense bluff recession. The erosion process induces debris deposition, which may be able to protect the bluff toe from wave action for a while. The bluffs in our study receded at different rates, despite proximity, in response to spatial and temporal differences in wave energy distribution. Based on results, we propose a bluff erosion cycle model for the studied area and infer current erosion vulnerability.Keywords: Short-term events, decadal mobility, wave exposition, bluff cycle model.RESUMO. Nas últimas décadas, questões relativas à erosão de falésias marinhas têm sido importantes ao longo das costas ao redor do mundo, especialmente devido à expansão urbana nessas áreas. Torna-se, portanto, necessário entender os fatores por trás do processo de erosão destas falésias, a fim de evitar perdas econômicas, sociais e ambientais. Este estudo analisou como o grau de exposição às ondas muda ao longo do tempo, no espaço entre 1948 e 2008, e também os impactos desta modificação sobre três falésias com mesma litologia, durante o intervalo de 1953-2008. Distâncias erodidas e taxas de erosão anual foram obtidas através da análise de imagens de satélite e aérea para os intervalos de tempo de 1953-1970, 1970-1995 e 1995-2008. A correlação entre o recuo das falésias e a ação das ondas foi baseada no comportamento das alturas significativas médias anuais, ocorrência de onda extremas e modelagem da variação espaço/temporal da energia de onda de 1953 a 2008. O recuo das três falésias estudadas apresenta um incremento no sentido norte-sul, variando de 51, 43 a 18 m, resultando em taxas erosivas anuais de 0,8; 0,69 e 0,43 m/ano, respectivamente. Em geral, taxas de erosão parecem menores durante longos períodos (63 anos) em comparação com taxas de curto prazo (8-25 anos). Além disso, a mudança na distribuição de energia de onda modelada se mostra de acordo com a variabilidade espaço/temporal das taxas de erosão. No entanto, os resultados mostram que fases de alta energia de ondas não estão necessariamente relacionadas com intenso recuo das falésias. Discute-se que processo de erosão induz a deposição de detritos na base da falésia, que podem ser capazes de proteger da ação de onda até que sejam transportados para o mar. Portanto, conclui-se que falésias homogêneas mostram ritmos diferentes de recessão que respondem a alterações espaciais e temporais em distribuição de energia de onda. Além disso, a partir do modelo esquemático do ciclo de erosão no pé de falésias proposto neste estudo, é possível inferir a atual vulnerabilidade de erosão das falésias estudadas com base nos resultados obtidos.Palavras-chave: Eventos a curto prazo, mobilidade decadal, exposição às ondas, modelo evolutivo de falésias.

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Tang, Wen Hua, Ren Zhang Qian, Huai Yu Zou, and Bo Ming Pi. "The Optimal Selection Investigation on Flame Holder for Afterburner." Advanced Materials Research 354-355 (October 2011): 201–4. http://dx.doi.org/10.4028/www.scientific.net/amr.354-355.201.

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In order to determine the bluff body and slitted bluff body flame stability and combustion performance, atmospheric low-speed experimental platform was used to carry out diesel fog combustion experiment for two types of bluff body, which are respectively streamlined V-form added straight channel and triangle V-form added straight channel. Results have shown that flame stability and combustion efficiency of streamlined bluff body is orderly slit width at 13mm, 6mm, 0mm and the triangular bluff body is orderly slit width at 6mm, 13mm, 0mm. Optimal combustion performance is streamlined bluff body with slit width 13mm.

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Mollamahdi, Mahdi, and Seyed Abdolmehdi Hashemi. "A numerical study on the flame characteristics and pollutant emissions in a premixed burner: Comparison between porous and solid bluff bodies." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 234, no. 3 (July 15, 2019): 353–64. http://dx.doi.org/10.1177/0957650919861839.

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The effects of porous and solid bluff bodies in the combustion chamber on flame stability limits, gas and solid temperature distributions, pressure drop, methane conversion rate, and CO and NO emissions are examined numerically. The porous and solid bluff bodies are made of SiC with the inner diameter of 50 mm, the outer diameter of 90 mm, and the length of 22 mm. In this study, Renormalization Group k–ε is used for modeling of turbulence. Eddy dissipation concept is selected for modeling of the interaction between turbulence and chemistry. A reduced mechanism based on GRI 3.0 consisting of 16 species and 41 reactions is employed to model methane combustion. The results indicate that the upper flame stability limit can be diminished by adding porous bluff body in the combustion chamber instead of the solid bluff body. Besides, the pressure drop, CO and NO emissions in the combustion chamber with solid bluff body are higher than those of porous bluff body, while the methane conversion rate increases by replacing porous bluff body instead of solid bluff body in the combustion chamber.

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Hojan, Marcin, and Mirosław Więcław. "Influence of meteorological conditions on aeolian processes along the Polish cliff coast." Baltica 27, no. 1 (September 6, 2014): 63–74. http://dx.doi.org/10.5200/baltica.2014.27.07.

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This article presents aeolian landforms and meteorological parameters affecting aeolian processes on the south Baltic coastal cliffs of Poland. The analysis was conducted for two weather stations at different locations. The bluffs in the vicinity of the stations have similar geological structure, but differ in height. Velocity and direction of the wind, as well as precipitation, are of dominating importance. Dispelling the cliff starts at wind speeds of two–three ms-1. At this speed, the distance at which the material is transported is short and is only a few meters, while for the transport of fine sand and dust on the top of the bluff the wind speed must be over 10 ms-1. It was observed that such speeds of the wind or gust are characteristic of days with an average wind velocity of at least six ms-1. The number of days with potential deflation on the bluff is four times higher in the area of Ustka than in the Świnoujście region. On average, the bluff in Ustka can be dispersed by wind throughout 33 days in a year, while the one in Wolin in less than eight days. Erosive and accumulative eolian forms are small, their sizes are generally less than one meter, only with rhythmic swelling to the size of several meters.

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Eyles, N., and K. W. F. Howard. "A hydrochemical study of urban landslides caused by heavy rain: Scarborough Bluffs, Ontario, Canada." Canadian Geotechnical Journal 25, no. 3 (August 1, 1988): 455–66. http://dx.doi.org/10.1139/t88-051.

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Scarborough Bluffs is a 15 km long stretch of the Lake Ontario shoreline east of downtown Toronto. This heavily urbanized area currently represents Canada's most serious erosion problem. The worst affected zone is 1.5 km long and lies along South Marine Drive where 50 m high bluffs are failing by shallow retrogressive failures of jointed glacial clays over underlying deltaic sands and clays. The erosion rate is about four times that for the coastline as a whole.Heavy rains in the Toronto area in August and September 1986 produced a spate of slope failures and mud flows. Particularly heavy storms on September 10 and 29 triggered extensive retrogressive slope failures at South Marine Drive. Hydrochemical investigations of discharge waters suggest that slope failure was caused by surface runoff on the bluff top recharging lower slope areas by infiltration through joints in the upper clay capping. Discharge of water from the lower slope is impeded by less permeable barriers in the deltaic stratigraphy at the site and by a cover of clayey slope debris. Data suggest that provision for adequate drainage of the bluff top, by interceptor drains, is a prerequisite for controlling slope behaviour in the area. Key words: slopes, erosion, groundwater, hydrochemical, recharge, drainage.

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Farber, David T., and Heather Weitzner. "BLUFF STABILIZATION AND PROTECTION ON THE GREAT LAKES; A CASE STUDY." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 5. http://dx.doi.org/10.9753/icce.v36.risk.5.

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The focus of this project was to design a shoreline remediation system that would stabilize and protect an eroding bluff on Lake Ontario. The significance of this project is the innovative techniques utilized to stabilize a 100-foot-high, almost 45Âº angle bluff from the erosive forces caused by waves, wind, groundwater, and rain. Geosynthetics, blown on compost material, and the installation of an irrigation system were all tools that were utilized for bluff stabilization, while an armor stone revetment was used to protect the toe of the bluff. This project may be used as an example for other shorelines experiencing similar bluff failure and erosional issues.

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Asep Supriadi, Adhes Gamayel, Murtalim, Ujiburrohman, and Riyan Ariyansah. "PENGARUH BENTUK PENAMPANG BLUFF BODY PERSEGI, BELAH KETUPAT, DAN SEGITIGA TERHADAP TEGANGAN LISTRIK YANG DIHASILKAN OLEH PIEZOELEKTRIK." Jurnal Teknik Mesin Mechanical Xplore 2, no. 2 (March 2, 2022): 19–25. http://dx.doi.org/10.36805/jtmmx.v2i2.2169.

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Piezoelektrik adalah perangkat pemanen energi skala mikro yang mengkonversikan energi mekanik menjadi energi listrik. Ketika ada tumbukan pada material piezoelektrik maka akan menyebabkan terjadinya getaran serta menghasilkan tegangan dan defleksi. Metode penelitian ini yaitu dengan mengamati piezoelektrik yang bergetar akibat aliran udara yang melewati penampang bluff body untuk menghasilkan tegangan listrik.. Dimana dimensi dan tinggi dalam satu penampang bluff body persegi, belah ketupat, dan segitiga memiliki ukuran yang sama yaitu 7 cm. Kecepatan aliran angin yang dipakai yaitu 5 m/s, 7 m/s, dan 9m/s. Penelitian dilakukan di dalam terowongan angin dan jarak penampang bluff body terhadap piezoelektrik yaitu 80 cm. Hasil dari variabel bentuk penampang bluff body yang menghasilkan tegangan listrik tertinggi yaitu pada penampang bluff body belah ketupat. Hasil dari variabel kecepatan yang menghasilkan tegangan listrik tertinggi yaitu pada kecepatan 9 m/s menghasilkan tegangan listrik 5,58 volt penampang bluff body belah keupat. Akibat adanya olakan maka sirip bergerak keatas dan kebawah menumbuk piezoelektrik. Piezoelectric is a micro-scale energy harvesting device that converts mechanical energy into electrical energy. When there is a collision with the piezoelectric material, it will cause vibration and produce stress and deflection. This study aims to determine the effect of the shape of the cross section of the bluff body on the electric voltage generated by the piezoelectric. This research method is to observe the piezoelectric vibrating due to the flow of air that passes through the cross section of the bluff body to produce an electric voltage. The independent variables in this study were the shape of the bluff body, and the speed of the wind flow. Where the dimensions and height in one cross-section of the square bluff body, rhombus, and triangle have the same size, which is 7 cm. The wind speed used is 5 m/s, 7 m/s, and 9m/s. The research was conducted in a wind tunnel and the cross-sectional distance between the bluff body to the piezoelectric is 80 cm. The result of the variable cross-sectional shape of the bluff body that produces the highest electrical voltage is the rhombic bluff body cross-section. The result of the speed variable that produces the highest electrical voltage, which is at a speed of 9 m/s, produces an electric voltage of 5.58 volts across the body of the kept cliff. Due to the oscillations, the fins move up and down to hit the piezoelectric.

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Reber. "Calling Maria's Bluff." American Journal of Psychology 134, no. 2 (2021): 247. http://dx.doi.org/10.5406/amerjpsyc.134.2.0247.

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Menzer, Paul D. "The Olympic Bluff." Ben Jonson Journal 11, no. 1 (January 2004): 41–66. http://dx.doi.org/10.3366/bjj.2004.11.1.6.

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Woodward, Phil. "Call my bluff." Significance 3, no. 1 (March 2006): 30–32. http://dx.doi.org/10.1111/j.1740-9713.2006.00150.x.

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Mandal, S., C. S. P. Ojha, P. Bhargava, Hiroshi Noda, Akihiko Nakayama, T. Nozuo, T. Tamura, et al. "CFD (Bluff Body)." Wind Engineers, JAWE 2001, no. 89 (2001): 317–40. http://dx.doi.org/10.5359/jawe.2001.89_317.

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Richardson, Albert S. "Bluff Body Aerodynamics." Journal of Structural Engineering 112, no. 7 (July 1986): 1723–26. http://dx.doi.org/10.1061/(asce)0733-9445(1986)112:7(1723).

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Sanders, Bernard, and Alan Greenspan. "Calling Greenspan's Bluff." Monthly Review 55, no. 5 (October 2, 2003): 10. http://dx.doi.org/10.14452/mr-055-05-2003-09_2.

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Möller, Key. "The Beijing bluff." Survival 48, no. 2 (June 2006): 137–46. http://dx.doi.org/10.1080/00396330600765609.

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Smuck, Matthew. "Blind Man's Bluff." Spine Journal 9, no. 6 (June 2009): 518–19. http://dx.doi.org/10.1016/j.spinee.2009.04.012.

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Newton, Steven. "Call creationism's bluff." New Scientist 212, no. 2833 (October 2011): 30–31. http://dx.doi.org/10.1016/s0262-4079(11)62447-0.

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Harder, Ben. "Calling Death's Bluff." Science News 170, no. 13 (September 23, 2006): 202. http://dx.doi.org/10.2307/4017200.

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Vanderburg, Willem H. "The Knowledge Bluff." Bulletin of Science, Technology & Society 27, no. 5 (October 2007): 401–7. http://dx.doi.org/10.1177/0270467607307224.

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Pauketat, Timothy R., Robert F. Boszhardt, and Michael Kolb. "Trempealeau’s Little Bluff." Midcontinental Journal of Archaeology 42, no. 2 (July 1, 2017): 168–99. http://dx.doi.org/10.2307/26599955.

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Abstract Archaeological and geomorphological investigations of Little Bluff (47Tr32), in Trempealeau, Wisconsin, reveal how and, possibly, why this loess-capped sandstone ridge spur was anthropogenically altered in the mid-eleventh century A.D. Project excavation units and trenches dug in 2010–2011 revealed the timing, rate of completion, structure, symmetry, and orientation of the construction. In addition to delineating construction details and associated archaeological features, our research suggests that Cahokians, by sculpting and rebuilding this ridge spur, were actively positioning themselves vis-à-vis the wider Mississippi Valley landscape, if not the cosmos generally.

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Kasum, Kasum, Fajar Mulyana, and Adhes Gamayel. "PIEZOELEKTRIK SEBAGAI PEMANEN ENERGI DENGAN PENAMBAHAN BLUFF BODY SEGITIGA." Simetris: Jurnal Teknik Mesin, Elektro dan Ilmu Komputer 9, no. 2 (November 20, 2018): 747–52. http://dx.doi.org/10.24176/simet.v9i2.2291.

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Piezoelektrik adalah salah satu alat pemanen energi yang menghasilkan energi listrik ketika mengalami defleksi. Penelitian mengenai bentuk penampang bluff body terhadap tegangan listrik yang dihasilkan piezoelektrik telah dilakukan, namun penelitian tentang potensi bluff body segitiga masih belum dilakukan. Metode penelitian yang dilakukan adalah mengukur tegangan listrik dari piezoelektrik dengan sistem kantilever. Bluff body yang dipasang sebagai penghalang adalah bluff body berpenampang segitiga dengan panjang alas dan tinggi sama yaitu, 1 cm, 2 cm, dan 3 cm. Penelitian ini dilakukan menggunakan terowongan angin mini dengan kecepatan angin 3 m/s dan jarak piezoelektrik terhadap bluff body adalah 50 mm. Hasil yang didapatkan adalah bluff body penampang segitiga 1 cm memiliki nilai efektif tertinggi yaitu 5,21 x 10-3 volt. Aliran udara saat melewati ujung segitiga bagian atas menyebabkan terjadi olakan lebih banyak dibandingkan saat aliran udara melewati alas segitiga. Semakin besar olakan yang terjadi maka udara yang menumbuk permukaan piezoelektrik semakin besar sehingga nilai efektifnya menjadi tinggi.

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Sataer, Guzalay, Mohamed Sultan, Mustafa Kemal Emil, John A. Yellich, Monica Palaseanu-Lovejoy, Richard Becker, Esayas Gebremichael, and Karem Abdelmohsen. "Remote Sensing Application for Landslide Detection, Monitoring along Eastern Lake Michigan (Miami Park, MI)." Remote Sensing 14, no. 14 (July 20, 2022): 3474. http://dx.doi.org/10.3390/rs14143474.

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We assessed the nature and spatial and temporal patterns of deformation over the Miami Park bluffs on the eastern margin of Lake Michigan and investigated the factors controlling its observed deformation. Our approach involved the following steps: (1) extracting bluff deformation rates (velocities along the line of sight of the satellite) using a stack of Sentinel-1A radar imagery in ascending acquisition geometry acquired between 2017 and 2021 and applying the Intermittent Small Baseline Subset (ISBAS) InSAR time series analysis method; (2) generating high-resolution (5 cm) elevation models and orthophotos from temporal unmanned aerial vehicle (UAV) surveys acquired in 2017, 2019, and 2021; and (3) comparing the temporal variations in mass wasting events to other relevant datasets including the ISBAS-based bluff deformation time series, lake level (LL) variations, and local glacial stratigraphy. We identified areas witnessing high line-of-sight (LOS) deformation rates (up to −21 mm/year) along the bluff from the ISBAS analysis and seasonal deformation patterns associated with freeze-thaw cycles, suggesting a causal effect. The acceleration of slope failures detected from field and UAV acquisitions correlated with high LLs and intensified onshore wave energy in 2020. The adopted methodology successfully predicts landslides caused by freezes and thaws of the slope face by identifying prolonged slow deformation preceding slope failures, but it does not predict the catastrophic landslides preceded by short-lived LOS deformation related to LL rise.

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Teimourian, Amir, and Hanifa Teimourian. "Vortex Shedding Suppression: A Review on Modified Bluff Bodies." Eng 2, no. 3 (July 27, 2021): 325–39. http://dx.doi.org/10.3390/eng2030021.

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Vortex shedding phenomenon behind bluff bodies and its destructive unsteady wake can be controlled by employing active and passive flow control methods. In this quest, researchers employed experimental fluid dynamics (EFD), computational fluid dynamics (CFD) and an analytical approach to investigate such phenomena to reach a desired outcome. This study reviews the available literature on the flow control of vortex shedding behind bluff bodies and its destructive wake through the modification of the geometry of the bluff body. Various modifications on the bluff body geometries namely perforated bluff bodies, permeable and porous mesh, corner modification and wavy cylinder have been reviewed. The effectiveness of these methods has been discussed in terms of drag variation, wake structure modifications and Strouhal number alteration.

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Nyitrai, Endre. "The Advantages and Disadvantages of Tactical Bluff in the Investigation against Criminal Organisations in Hungary." Analele Universității din Oradea. Seria: Relații Internaționale și Studii Europene 2022 (2020): 217–28. http://dx.doi.org/10.58603/bmji4698.

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I have conducted several consultations and interviews with police officers (investigators, detectives, inspectors) pursuing criminal procedures, also with prosecutors, judges and attorneys (hereinafter: criminalists) on what they mean by tactical bluff. I understood, that some criminalists do not differentiate between colloquial bluff and tactical bluff, that can be the source of several mistakes.

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Yokoi, Yoshifumi. "Pilot study about the micro hydropower generation by use of flow induced vibration phenomenon." EPJ Web of Conferences 180 (2018): 02122. http://dx.doi.org/10.1051/epjconf/201818002122.

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In order to construct a micro power generation system using a piezo-electric element, power generation was tried using excitation oscillation of the bluff cylinder by the vortex shedding from the bluff cylinder. The bluff cylinder consists of a board spring section in which the piezo-electric element was attached, and a body section. The bluff cylinder was inserted into the water flow, the shape and the submersion depth of the bluff cylinder, and the flow velocity were varied, and the power generation characteristic was investigated. As a result, it was found that it can generate electricity by vortex excitation. It was found that the length and the submersion depth of the body section influence power generation. It was shown that the power generation characteristic changes with cross-sectional shape of the bluff cylinder. The most suitable state was the case where the submersion depth was set to 140 mm with a circular cylinder with a span length of 250 mm. It is important to choose the power generation object which suited the use purpose.

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HARASHIMA, Taiji. "Bubbles, Bluffs and Greed." Theoretical and Practical Research in the Economic Fields 6, no. 1 (June 30, 2015): 21. http://dx.doi.org/10.14505/tpref.v6.1(11).02.

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A rational bubble cannot theoretically exist if people have infinite horizons. This paper shows that a bubble-like phenomenon can be generated by a “bluff” even if people are rational and have infinite horizons. A bluff is defined as the behavior of an agent who pretends to possess private information to gain profits, particularly (false or misleading) information that the representative household’s rate of time preference (RTP RH) has changed. An alternative definition of the representative household indicates that households must ex ante generate an expected RTP RH to behave optimally, but the expected RTP RH has to be generated based on beliefs about the RTP RH. Bluffers exploit the opportunities derived from the fragile nature of the expected RTP RH. The driving force behind bluffs is greed because bluffers do not work hard to gain profits by producing and selling better goods and services more cheaply, but by disseminating contaminated information, or acting in such a way to mislead people into believing the expected RTP RH has changed.

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Siddiqui, Naseeb Ahmed, and Martin Agelin-Chaab. "Nature-inspired solutions to bluff body aerodynamic problems: A review." Journal of Mechanical Engineering and Sciences 15, no. 2 (June 10, 2021): 8095–140. http://dx.doi.org/10.15282/jmes.15.2.2021.13.0638.

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This review investigates the nature-inspired techniques for the optimization of the aerodynamic forces on bluff bodies. To provide a rich understanding of these nature-inspired phenomena, three distinct zones of the species fishes (nektons), birds (avians) and the fast running land animals are considered. This allows contextualizing different capabilities of the species in different environmental necessities. The review follows a trend in which drag reduction capabilities of individual parts of these species, including body shape & size, tails, fins, surface structure, wings, and wingtips, have been explored in detail. By focusing on specific parts, the review examined the methods and physics involved, which provides space to narrate the development of ideas and our current understanding of the nature-inspired drag reduction and their application to bluff body aerodynamics. Consequently, nature-inspired promising areas for future endeavor related to the bluff body has been discussed in detail. It was found that, though, aerospace field has found several bird inspired application but the bluff body flow modification have only few. Similar is the case with fishes and land animals which have not been explored yet for aerodynamic use on the bluff bodies. The crucial importance of passive devices are also highlighted along with the review of their application on the bluff bodies inspired by nature. Furthermore, several of nature-inspired techniques are proposed and compared to facilitate the research in this direction. It provides a fundamental method to develop nature-inspired flow control devices for the bluff bodies.

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Ghazian Arabi, Mahsa, Ali Farhadzadeh, and Ali Khosravi. "RECESSION OF PREDOMINANTLY SANDY BLUFFS." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 78. http://dx.doi.org/10.9753/icce.v36.sediment.78.

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Climate change and sea level rise are anticipated to accelerate coastal erosion, a major societal issue during the past half-century (Hapke, et al., 2009). While important progress has been made in predicting sandy beach responses to various ocean climates, a similar progress has not been made for coastal bluffs. Coastal bluff recession is a natural process that can become a hazard when it endangers buildings and developed properties. Despite some early works on cohesive shoreline erosion mechanisms (Dalrymple, et al., 1986; Sunamura, 1985), prediction of bluff recession still remains one of the main questions in coastal zone management. Several experiment studies were conducted in wave flumes to investigate the effective parameter. Earlier experiments focused mainly on hard cliff and cohesive bluffs erosion in the 1970s, under normally incident waves and have been reported by Sanders (1968), Horikawa and Sunamura (1970), and Sunamura (1983). During the 1980sâ€“1990s a number of studies were conducted to understand erosion of cohesive coastal profiles with or without an overlying veneer of sand (Nairn, 1986, and Skafel and Bishop, 1994). These works used artificial or prototype clays for the cliff and focused primarily on the erosion process of the clay at beach or foreshore. A recent study by Caplain et al. (2011) investigates the effect of wave climate on the rate of sandy cliff recession in a wave flume. They reported observations of sand movements, sand bars dynamics and cliff recession rate.

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Kantoch, Robert, Agnieszka Wawrzak, and Artur Tyliszczak. "Numerical analysis of influence of various bluff-body shapes on diffusion flame dynamics." Journal of Physics: Conference Series 2367, no. 1 (November 1, 2022): 012016. http://dx.doi.org/10.1088/1742-6596/2367/1/012016.

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Abstract In this paper, various bluff-body shapes (cylindrical, square, star) and two different surface topologies (smooth, wavy) are applied as passive tools for controlling a non-premixed hydrogen flame in a combustion chamber. We focus on the dynamics of the flame and its time-averaged characteristics in the close vicinity of an injection system within formed recirculation zones and also in a far-field. The research is performed with the help of large-eddy simulations (LES) method using the ANSYS Fluent software and a high-order academic code SAILOR. Flame behaviour is found to be strongly dependent on the geometry of the bluff-body whereas its wall topology affects the flame characteristics only slightly. In the cases with the square and star bluff-body, small vortical structures originating at the corners deform large vortical structures created by the Kelvin-Helmholtz instability mechanism. This intensifies the mixing and combustion process and, in the configuration with the square shape bluff-body, translates to the shortening of the recirculation zone by 15% of the equivalent bluff-body diameter and the flame, which in the axis develops closer to the bluff-body. The star shape leads to the most uniform flame at the radial border or the recirculation zone.

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Sadewo, Leo Fendi, Riyan Ariyansah, Adhes Gamayel, Sefnath J. E. Sarwuna, and Ujiburrohman U. "PENGARUH VARIASI UKURAN PENAMPANG BLUFF BODY BELAHKETUPAT TERHADAP TEGANGAN LISTRIK YANG DIHASILKAN PIEZOELEKTRIK." Journal Teknik Mesin, Elektro, Informatika, Kelautan dan Sains 2, no. 1 (July 12, 2022): 27–33. http://dx.doi.org/10.30598/metiks.2022.2.1.27-33.

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Abstrak Piezoelektrik adalah komponen elektronika yang biasanya digunakan dalam perangkat yang berhubungan dengan bunyi atau bisa juga sebagai tranduser yang dapat mengubang energi mekanik menjadi energi listrik ketika menerima getaran. Namun, dimensi piezoelektrik yang kecil dan tipis menyebabkan defleksi yang kecil yang dihasilkan oleh piezoelektrik tersebut, itulah kelemahan yang dimiliki oleh piezoelektrik. Oleh karena itu, piezoelektrik digolongkan sebagai penghasil energi listrik untuk tingkatan micro. Tujuan dari penelitian ini adalah untuk mengetahui besar potensi energi listrik yang dihasilkan pada piezoelektrik pemanen energi dengan berdasarkan pola aliran fluida yang melewati penghalang bluff body belah ketupat dengan tiga variasi ukuran 5 cm, 7 cm, dan 9 cm. Variabel bebas dalam penelitian ini adalah variasi ukuran bluff body belah ketupat, dan variasi kecepatan aliran angin yaitu 5 m/s, 7 m/s, dan 9 m/s. Dimana variasi bluff body belah ketupat dengan berbeda ukurannya, Penelitian dilakukan di dalam terowongan angin dan jarak penampang bluff body terhadap piezoelektrik yaitu 80 cm. Hasil dari variabel variasi ukuran penampang bluff body belah ketupat yang menghasilkan tegangan listrik tertinggi yaitu pada penampang bluff body belah ketupat dengan ukuran 7 cm, dengan variabel kecepatan yang menghasilkan tegangan listrik tertinggi yaitu pada kecepatan 9 m/s menghasilkan tegangan listrik 5,58 volt dengan penampang bluff body belah ketupat ukuran 7 cm. Berdasarkan penelitian tersebut dengan adanya olakan yang diakibatkan oleh fluida yang mengalir, maka sirip bergerak ke atas dan ke bawah menumbuk piezoelektrik. Semakin besar aliran udara dan olakannya, Maka gerakan sirip ke atas dan ke bawah akan semakin besar. Hal ini terbukti dengan besar voltase yang dihasilkan oleh piezoelektrik.

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Umyshev, Dias, Abay Dostiyarov, Andrey Kibarin, Galya Tyutebayeva, Gaziza Katranova, and Darkhan Akpanbetov. "Experimental investigation of distance between v-gutters on flame stabilization and NOx emissions." Thermal Science 23, no. 5 Part B (2019): 2971–81. http://dx.doi.org/10.2298/tsci180503007u.

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Blow-off performance and NOx emissions of the propane and air mixture in a rectangular combustion chamber with bluff bodies were investigated experimentally and numerically. The effects of distance between bluff bodies on NOx emissions, the blow-off limit, and exhaust gas temperature were examined. It was observed that NOx emissions are highly dependent on distance between V-gutters. The re-circulation zone behind the bluff body expands in width based on the decrease of distance between V-gutters, and expands in length with the increase of inlet velocity. The temperature fields behind the bluff body show a similar change, the temperature behind the bluff body reaches its highest when the distance between V-gutters reaches 20 mm, meaning it has better flame stability. The blow-off limit is significantly improved with the decrease of distance between V-gutters. The blow-off limit is greatly improved by reducing the distance between the V-gutters. Maximum blow-off limit of 0.11 is reached in the case of 20 mm, compared with 0.16 at 50 mm at a speed of 10 m/s.

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Gamayel, Adhes. "Pengaruh Pemasangan Bluff Body Terhadap Karakteristik Pembakaran Biobriket." Semesta Teknika 17, no. 1 (November 25, 2015): 53–60. http://dx.doi.org/10.18196/st.v17i1.409.

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Biofuels are organic feedstock fuel produced by living organisms, such as solids, liquids, or gases. Biobriket combustion process is affected by the heating value biobriket constituent materials and the amount of air entering the biobriket combustion chamber. The purpose of this study isto determine the effect of variations of the bluff bodygeometry on the biobriket burning process. The independent variable used in this study, arethe fan rotation and the bluff bodygeometry. Fan rotation being used are 1000 rpm, 1200 rpm, 1400 rpm, 1600 rpm, 1800 rpm and 2000 rpm, while the bluff body geometry are round, triangle, square, hexagon and octagon. Triangular cross-section bluff body was noted to produce the highest temperature of 33.21 °C at 100 second. While the lowest temperature wasreached at 500 second with 31.18 oC. Fan rotation at 2000 rpm was found to produce the most rapid combustion,burnt out 10 grams of biobriket within 500 seconds.The conclusion to this study is the higher the fan rotation speed, the faster the combustion process of the biobriket. Triangular bluff body was found the best shape in this study.

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Mat Ali, Mohamed Sukri, Sheikh Ahmad Zaki Shaikh Salim, Mohamad Hafz Ismail, Sallehuddin Muhamad, and Muhammad Iyas Mahzan. "Aeolian Tones Radiated from Flow Over Bluff Bodies." Open Mechanical Engineering Journal 7, no. 1 (October 18, 2013): 48–57. http://dx.doi.org/10.2174/1874155x01307010048.

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Bluff body is a simple but a central shape for many engineering applications. The geometry shape of the bluff body characterises the behaviour of the flow over the bluff body, where a more complex flow structure is found near downstream. Shear layer separation is mainly responsible for the periodic global phenomena, that includes the generation of sound. The magnitude of the aerodynamically generated sound is dominated by the fluctuations of aerodynamics forces, i.e., drag and lift. The study also shows that the sound pressure field is shaped by the aeolian tones that is related strongly to the lift fluctuations of the bluff body. Amplitude and frequency of the fluctuating lift change naturally with the shape of a particular bluff body. Triangular cylinder exhibits the largest sound pressure level (41.9 dB) followed by ellipse and circular shapes. Square cylinder emits the lowest sound pressure level (36.7 dB). This corresponds to the longest downstream vortex formation length at which for a square cylinder the long vortex formation length provides space for more vortex to dissipate.

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Zhang, Changjiang, Lin Ding, Lin Yang, Zuomei Yang, Zesheng Yang, and Li Zhang. "Influence of Shape and Piezoelectric-Patch Length on Energy Conversion of Bluff Body-Based Wind Energy Harvester." Complexity 2020 (July 14, 2020): 1–10. http://dx.doi.org/10.1155/2020/3789809.

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The technology of scavenging ambient energy to realize self-powered of wireless sensor has an important value in practice. In order to investigate the effects of piezoelectric-patch length and the shape of front bluff body on energy conversion of the wind energy harvester by flow-induced vibration, the characteristics of a piezoelectric wind energy harvester based on bluff body are experimentally studied in this work. Four different section shapes of the bluff body, including triangular cylinder, trapezoidal cylinder, reverse trapezoidal cylinder, and square cylinder, are tested. The piezoelectric patch is attached on the leeward side of the bluff body. The lengths of piezoelectric patch are considered as 1.0D–1.4D (D is the characteristic length of the bluff body). It is found that the length of the piezoelectric patch and the shape of the front bluff body play a vital role in improving the performance of wind energy harvester. For the reverse trapezoidal cylinder and square cylinder, the back-to-back vortex-induced vibration (VIV) and galloping phenomenon can be observed. In addition, the energy harvesting performance of the reverse trapezoidal cylinder piezoelectric harvester is the best. The maximum average peak voltage of 1.806 V and the output power of P=16.3 μW can be obtained when external resistance and the length of piezoelectric patch are 100 KΩ and 1.1D, respectively.

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Hansl, Matthias. "Lüge, Bluff & Co." Kursbuch 53, no. 189 (2017): 9–25. http://dx.doi.org/10.5771/0023-5652-2017-189-9.

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Bardakhanov, S. P., S. A. Kozlov, Seiji Nakato, Kichiro Kimura, Yozo Fujino, Takanobu Ogawa, Satoru Okamoto, et al. "Bluff bodjjy (Fundamental Study)." Wind Engineers, JAWE 2001, no. 89 (2001): 129–56. http://dx.doi.org/10.5359/jawe.2001.89_129.

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MATSUDA, Kazutoshi, Hidesaku UEJIMA, Takashi SUGIMOTO, N. W. Mureithi, S. Goda, H. Kanki, T. Nakamura, et al. "Bluff Body (Dynamic Problem)." Wind Engineers, JAWE 2001, no. 89 (2001): 213–40. http://dx.doi.org/10.5359/jawe.2001.89_213.

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Knight, Vernon James, George E. Lankford, Erin Phillips, David H. Dye, Vincas P. Steponaitis, and Mitchell R. Childress. "The Holly Bluff style." Southeastern Archaeology 36, no. 3 (February 15, 2017): 195–213. http://dx.doi.org/10.1080/0734578x.2017.1286569.

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Fletcher, M. "It pays to bluff." Teaching Mathematics and its Applications 20, no. 2 (June 1, 2001): 75–77. http://dx.doi.org/10.1093/teamat/20.2.75.

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Meister, J. Patrick. "A Bluff-Bidding Exercise." Journal of Economic Education 42, no. 2 (April 6, 2011): 168–74. http://dx.doi.org/10.1080/00220485.2011.555719.

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J.B. "Introduction: Calling our bluff." Child & Youth Care Forum 25, no. 5 (October 1996): 277–79. http://dx.doi.org/10.1007/bf02589243.

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Singh, Sabita Madhvi. "Analysis of Vortex Around Bluff Body." Indian Journal of Applied Research 3, no. 6 (October 1, 2011): 223–26. http://dx.doi.org/10.15373/2249555x/june2013/74.

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Triyogi, Y., D. Suprayogi, and E. Spirda. "Reducing the drag on a circular cylinder by upstream installation of an I-type bluff body as passive control." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 223, no. 10 (June 5, 2009): 2291–96. http://dx.doi.org/10.1243/09544062jmes1543.

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The bluff body cut from a small circular cylinder that is cut at both sides parallel to the y-axis was used as passive control to reduce the drag of a larger circular cylinder. The small bluff body cut is called an I-type bluff body, which interacts with a larger one downstream. I-type bluff bodies with different cutting angles of θs = 0°(circular), 10°, 20°, 30°, 45°, 53°, and 65° were located in front and at the line axis of the circular cylinder at a spacing S/ d = 1.375, where their cutting surfaces are perpendicular to the free stream velocity vector. The tandem arrangement was tested in a subsonic wind tunnel at a Reynolds number (based on the diameter d of the circular cylinder and free stream velocity) of Re = 5.3×104. The results show that installing the bluff bodies (circular or sliced) as a passive control in front of the large circular cylinder effectively reduces the drag of the large cylinder. The passive control with cutting angle θs = 65° gives the highest drag reduction on the large circular cylinder situated downstream. It gives about 0.52 times the drag of a single cylinder.

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Fallaw, W., David Snipes, and Van Price. "Wandering With William Bartram: The Section At Silver Bluff, South Carolina." Earth Sciences History 13, no. 1 (January 1, 1994): 52–57. http://dx.doi.org/10.17704/eshi.13.1.pw32124312286527.

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In his famous book, William Bartram (1791) described a stratigraphic section at Silver Bluff on the Savannah River in Aiken County, South Carolina, as dark, laminated clay containing belemnites, overlain by clays, sand, marl, and a shelly bed containing numerous oysters. There are now no known occurrences of marine megafossils in outcrops along the Savannah in Aiken County. The wording of Bartram's description of Cretaceous outcrops along the Cape Fear River in North Carolina indicates that the lower part of the Silver Bluff section was described from notes made on the Cape Fear and from his father's diary. The description of the upper beds at Silver Bluff may have been transferred from the Cape Fear, where fossiliferous Pliocene beds overlie the Cretaceous. It is probable, however, that it was from notes made at an Eocene locality in Georgia, most likely Shell Bluff on the Savannah River.

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Thompson, Mark C., Thomas Leweke, and Kerry Hourigan. "Bluff Bodies and Wake–Wall Interactions." Annual Review of Fluid Mechanics 53, no. 1 (January 5, 2021): 347–76. http://dx.doi.org/10.1146/annurev-fluid-072220-123637.

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This review surveys the dramatic variations in wake structures and flow transitions, in addition to body forces, that appear as the motion of bluff bodies through a fluid occurs increasingly closer to a solid wall. In particular, we discuss the two cases of bluff bodies translating parallel to solid walls at varying heights and bluff bodies impacting on solid walls. In the former case, we highlight the changes to the wake structures as the flow varies from that of an isolated body to that of a body on or very close to the wall, including the effects when the body is rotating. For the latter case of an impacting body, we review the flow structures following impact and their transition to three-dimensionality. We discuss the issue of whether there is solid–solid contact between the bluff body and a wall and its importance to body motion.

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Meunier, P., S. Le Dizès, L. Redekopp, and G. R. Spedding. "Internal waves generated by a stratified wake: experiment and theory." Journal of Fluid Mechanics 846 (May 9, 2018): 752–88. http://dx.doi.org/10.1017/jfm.2018.278.

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This paper presents experimental and theoretical results on the internal waves emitted by a bluff body moving horizontally in a linearly stratified fluid. Three different bluff bodies (a sphere, a spheroid and a cylinder) have been used in order to study the effect of the shape of the bluff body, although most of the results are obtained for the sphere. Two types of internal waves have been observed experimentally: large wavelength lee waves generated by the bluff body itself and small wavelength coherent wake waves generated by the turbulent wake. First, the lee waves are separated from the wake waves by averaging the experimental measurements in the frame moving with the bluff body. The velocity amplitude of the lee waves scales as the inverse of the Froude number$F=2U_{B}/(ND)$for$F>2$(where$U_{B}$is the towing velocity,$D$the diameter and$N$the buoyancy frequency). This scaling proves that the internal waves are related to the drag of the bluff body which is due to the separation of the flow behind the bluff body. This separation is usually not taken into account in the classical models which assume that the flow is dipolar. The drag can be modelled as a point force in the Navier–Stokes equations, which gives a correct prediction of the structure and the amplitude of the lee waves. Second, the wake waves have been separated from the lee waves by averaging the velocity fields in the frame moving at the phase velocity of the waves. The phase velocity and the wavelength scale as$F^{-2/3}$and$F^{1/3}$respectively which correspond to the velocity and distance between same sign vortices of the von Kármán vortex street. A simplified model is derived for the internal waves emitted by the double row of moving point vortices of the von Kármán street. The amplitude of the wake waves is measured experimentally and seems to depend on the Reynolds number.

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Yang, Gelan, Huixia Jin, and Na Bai. "A Numerical Study on Premixed Bluff Body Flame of Different Bluff Apex Angle." Mathematical Problems in Engineering 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/272567.

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In order to investigate effects of apex angle (α) on chemically reacting turbulent flow and thermal fields in a channel with a bluff body V-gutter flame holder, a numerical study has been carried out in this paper. With a basic geometry used in a previous experimental study, the apex angle was varied from 45° to 150°. Eddy dissipation concept (EDC) combustion model was used for air and propane premixed flame. LES-Smagorinsky model was selected for turbulence. The gird-dependent learning and numerical model verification were done. Both nonreactive and reactive conditions were analyzed and compared. The results show that asαincreases, recirculation zone becomes bigger, and Strouhal number increases a little in nonreactive cases while decreases a little in reactive cases, and the increase ofαmakes the flame shape wider, which will increase the chamber volume heat release ratio and enhance the flame stability.

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Gibbs, Ann, Li Erikson, Benjamin Jones, Bruce Richmond, and Anita Engelstad. "Seven Decades of Coastal Change at Barter Island, Alaska: Exploring the Importance of Waves and Temperature on Erosion of Coastal Permafrost Bluffs." Remote Sensing 13, no. 21 (November 3, 2021): 4420. http://dx.doi.org/10.3390/rs13214420.

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Observational data of coastal change over much of the Arctic are limited largely due to its immensity, remoteness, harsh environment, and restricted periods of sunlight and ice-free conditions. Barter Island, Alaska, is one of the few locations where an extensive, observational dataset exists, which enables a detailed assessment of the trends and patterns of coastal change over decadal to annual time scales. Coastal bluff and shoreline positions were delineated from maps, aerial photographs, and satellite imagery acquired between 1947 and 2020, and at a nearly annual rate since 2004. Rates and patterns of shoreline and bluff change varied widely over the observational period. Shorelines showed a consistent trend of southerly erosion and westerly extension of the western termini of Barter Island and Bernard Spit, which has accelerated since at least 2000. The 3.2 km long stretch of ocean-exposed coastal permafrost bluffs retreated on average 114 m and at a maximum of 163 m at an average long-term rate (70 year) of 1.6 ± 0.1 m/yr. The long-term retreat rate was punctuated by individual years with retreat rates up to four times higher (6.6 ± 1.9 m/yr; 2012–2013) and both long-term (multidecadal) and short-term (annual to semiannual) rates showed a steady increase in retreat rates through time, with consistently high rates since 2015. A best-fit polynomial trend indicated acceleration in retreat rates that was independent of the large spatial and temporal variations observed on an annual basis. Rates and patterns of bluff retreat were correlated to incident wave energy and air and water temperatures. Wave energy was found to be the dominant driver of bluff retreat, followed by sea surface temperatures and warming air temperatures that are considered proxies for evaluating thermo-erosion and denudation. Normalized anomalies of cumulative wave energy, duration of open water, and air and sea temperature showed at least three distinct phases since 1979: a negative phase prior to 1987, a mixed phase between 1987 and the early to late 2000s, followed by a positive phase extending to 2020. The duration of the open-water season has tripled since 1979, increasing from approximately 40 to 140 days. Acceleration in retreat rates at Barter Island may be related to increases in both thermodenudation, associated with increasing air temperature, and the number of niche-forming and block-collapsing episodes associated with higher air and water temperature, more frequent storms, and longer ice-free conditions in the Beaufort Sea.

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Gunawan Tista, I. Putu Gede, I. Gusti Ngurah Putra Tenaya, and I. Gusti Ngurah Putu Sudanta. "Pengaruh Variasi Jarak Penghalang Segitiga di depan Silinder Arah Vertikal terhadap Drag." Jurnal Energi Dan Manufaktur 11, no. 1 (April 27, 2018): 11. http://dx.doi.org/10.24843/jem.2018.v11.i01.p03.

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Salah satu cara untuk menghemat energi pada pesawat terbang dan bluff body lainnya adalah dengan mengurangi drag. Drag erat hubungannya dengan separasi aliran. Semakin awal terjadi separasi maka drag semakin meningkat. Oleh karena itu upaya yang dilakukan untuk mengurangi drag adalah dengan memanipulasi medan aliran fluida. Manipulasi aliran bisa dilakukan secara pasif antara lain menempelkan sebuah sirip pada bluff body, melubangi bluff body, menambahkan spiral pada bluff body dan menempatkan penghalang yang lebih kecil didepan bluff body. Penelitian ini yaitu dengan cara menempatkan penghalang berbentuk segitiga didepan silinder. Dalam penelitian ini pengujian dilakukan pada wind tunnel, yang terdiri dari blower, pipa pitot, manometer, pipa silinder, dan segitiga penghalang. Penempatan penghalang divariasikan pada arah vertikal posisi y = 0, y = 5 mm, y = 10 mm, y = 15 mm, sedangkan posisi penghalang pada arah horisontal pada jarak 60 mm terhadap silinder dengan panjang sisi segitiga adalah 8 mm. Distribusi tekanan diperoleh dengan mengukur tekanan permukaan silinder pada 36 titik dengan interval 10o. Data yang diukur adalah tekanan permukaan silinder, tekanan statis, dan kecepatan aliran fluida. Hasil penelitian menunjukkan bahwa terjadi penurunan drag pada saat diberi penghalang segitiga dibandingkan dengan tanpa diberi penghalang segitiga. Nilai koefisien drag untuk silinder tanpa diberi penghalang yaitu 0.1276. Sedangkan dari variasi jarak penghalang pada arah vertikal diperoleh penurunan koefisien drag tertinggi adalah pada posisi y = 0 yaitu sebesar 0,0186. Besarnya penurunan drag pada posisi ini adalah 85,45% dibandingkan dengan tanpa penghalang. One of the ways to reduce energy consumption an airplane and the other bluff body is by decreasing the drag. The drag is closely related to the flow of separation. The early separation, then the drag will increase. Based on the fact the effort to decrease drag is conducted by manipulating the field of fluid flow. The stream manipulation can be done passively, for example, by attaching a fin at the bluff body, by making a hole on the bluff body, enhancing spiral at the bluff body and placing a smaller barrier, on front of bluff body. The experiment was done by placing a triangle rod on front of the cylinder. In the present research the experiment was conducted in a wind tunnel, which consisted of a blower, a pitot pipe, a manometer, a main cylinder pipe, and a triangle rod. The triangle was variation vertical positioned at y = 0 mm, y = 5 mm, y = 10 mm, y = 15 mm. while the position of barrier in the horizontal direction at 60 mm distance towards the cylinder with the triangle side length was 8 mm. Pressure distribution was measured on 36 points at the cylinder surface with an interval of 100. The measured data was the pressure of cylinder surface, the static pressure, and the airflow speed.The research results showed that the triangle rod could decrease the drag of the main cylinder. The Coefficient drag for the cylinder without the triangle rod was 0, 1276 while the variation of barrier in the vertical direction obtained the biggest decrease of the coefficient of the drag with the triangle rod happened at position y = 0, which was 0, 0186. The magnitude of the drag reduction in this position was 85, 45% compared without barrier.

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