• Wind and Structures
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• v.16 no.1
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• pp.1-23
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• 2013

The wind-induced transient response of internal pressure following the creation of a sudden dominant opening during the occurrence of high external pressure, in low-rise residential and industrial buildings was numerically investigated. The values of the ill-defined parameters namely the flow contraction coefficient, loss coefficient and the effective slug length were calibrated by matching the analytical response with the computational fluid dynamics predictions. The effect of a sudden i.e., "instantaneously created" windward opening in the Texas Technical University (TTU) test building envelope was studied for two different envelope flexibility-leakage combinations namely: (1) a quasi-statically flexible and non-porous envelope and (2) a quasi-statically flexible and porous envelope. The responses forced by creating the openings at different time leads/lags with respect to the occurrence of the peak external pressure showed that for cases where the openings are created in close temporal proximity to the peak pressure, the transient overshoot values of internal pressure could be higher than the peak values of internal pressure in the pre-sequent or subsequent resonant response. In addition, the influence of time taken for opening creation on the level of overshoot was also investigated for the TTU building for the two different envelope characteristics. Non-dimensional overshoot factors are presented for a variety of cavity volume-opening area combinations for (1) buildings with rigid/quasi-statically flexible non-porous envelope, and (2) buildings with rigid/quasi-statically flexible and porous envelope (representing most low rise residential and industrial buildings). While the factors appear slightly on the high side due to conservative assumptions made in the analysis, a careful consideration regarding the implication of the timing and magnitude of such overshoots during strong gusts, in relation to the steady state internal pressure response in cyclonic regions, is warranted.

• Journal of Physiology & Pathology in Korean Medicine
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• v.31 no.4
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• pp.201-212
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• 2017

This study draws pattern differentiations of headache disorders on the ground of modern clinical applications and Korean medical literature. Categorization and symptoms of headache disorders are based on International Classification of Headache Disorders 3rd edition(beta version). And clinical papers are searched in China Academic Journals(CAJ) of China National Knowledge Infrastructure(CNKI). In the aspect of eight principle pattern identification, primary headache occurs due to lots of yang qi and has more inner pattern rather than exterior pattern, heat pattern rather than cold pattern, excess pattern rather than deficiency pattern. And primary headache is related with liver in the aspect of visceral pattern identification and blood stasis, wind and phlegm are relevant mechanisms. Migraine without aura is associated with ascendant hyperactivity of liver yang, phlegm turbidity, sunken spleen qi, wind-heat, blood deficiency or yin deficiency. Migraine with aura is mainly related with wind and it's major mechanisms are ascendant hyperactivity of liver yang, liver fire, yin deficiency of liver and kidney, blood deficiency or liver depression and qi stagnation. High repetition rate of tension-type headache can be identified as heat pattern or excess pattern. And trigeminal autonomic cephalalgias can also be accepted as heat pattern or excess pattern when the occurrence frequency is high and is relevant to combined pattern with excess pattern of external contraction and deficiency pattern of internal damage based on facial symptoms by external contraction and nervous and anxious status by liver deficiency. This study can be expected to be Korean medical basis of clinical practice guidelines on headache by proposing pattern identifications corresponding to the western classifications of headache disorders.

• Wind and Structures
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• v.35 no.1
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• pp.55-66
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• 2022

Tall buildings are often subjected to steady and unsteady forces due to external wind flows. Measurement and mitigation of these forces becomes critical to structural design in engineering applications. Over the last few decades, many approaches such as modification of the external geometry of structures have been investigated to mitigate wind-induced load. One such proven geometric modification involved the rounding of sharp corners. In this work, we systematically analyze the impact of rounded corner radii on the reducing the flow-induced loading on a square cylinder. We perform 3-Dimensional (3D) simulations for high Reynolds number flows (Re=1 × 105) which are more likely to be encountered in practical applications. An Improved Delayed Detached Eddy Simulation (IDDES) method capable of capturing flow accurately at large Reynolds numbers is employed in this study. The IDDES formulation uses a k-ω Shear Stress Transport (SST) model for near-wall modelling that prevents mesh-induced separation of the boundary layer. The effects of these corner modifications are analyzed in terms of the resulting variations in the mean and fluctuating components of the aerodynamic forces compared to a square cylinder with no geometric changes. Plots of the angular distribution of the mean and fluctuating coefficient of pressure along the square cylinder's surface illustrate the effects of corner modifications on the different parts of the cylinder. The windward corner's separation angle was observed to decrease with an increase in radius, resulting in a narrower and longer recirculation region. Furthermore, with an increase in radius, a reduction in the fluctuating lift, mean drag, and fluctuating drag coefficients has been observed.

• Journal of Korean Medical classics
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• v.26 no.2
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• pp.133-174
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• 2013

Objective : Malaria(瘧疾) is a disease that's main symptom is paroxysm - a cyclical occurrence of sudden coldness followed by rigor and then fever. Since the introduction of the cause and mechanism of malaria(瘧疾) in the "Suwen(素問)", including Cold malaria(寒瘧), Warm malaria(溫瘧), Heat malaria(癉瘧) and Wind malaria(風瘧), there has been over 20 different kinds of malaria, each of which are introduced in multiple medical texts. Method : Through comparison between "Suwen(素問)" and other medical texts, the categories, causes and mechanisms of malaria can be analysed and organized to overview the whole feature of it. Results & Conclusion : External pathogens of malaria(瘧疾) are wind(風), cold(寒), summerheat (暑), dampness(濕), miasmic toxin(瘴), pestilence(疫), ghost(鬼). Internal pathogens of malaria(瘧疾) are dietary irregularities(飮食不節), overexertion and fatigue(勞倦), phlegm(痰), seven emotion(七情). Malaria can be categorized into four groups according to the pathological mechanism that leads to paroxysm. They are latency of disease(伏氣), external contraction(外感), internal damage(內傷), and combination of disease(合病). Malaria-Paroxysm(瘧疾發作) occurs when the three following factors collide strongly : defense qi(衛氣), latent qi(伏邪) and external pathogen(新邪). When collision of the three factors takes place in the interior(裏), the body experiences chills. When it takes place in the exterior(表), the body experiences fever. The cyclical occurrence of Malaria-Paroxysm follows the circulation of defense qi.

• Wind and Structures
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• v.27 no.2
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• pp.101-109
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• 2018

Wall jet flow exists widely in engineering applications, including the simulation of thunderstorm downburst outflows, and has been investigated extensively by both experimental and numerical methods. Most previous studies focused on the scaling laws and self-similarity, while the effect of lip thickness and external stream height on mean velocity has not been examined in detail. The present work is a numerical study, using steady Reynolds-Averaged Navier Stokes (RANS) simulations at a Reynolds number of $3.5{\times}10^4$, of a turbulent plane wall jet with an external stream to investigate the influence of the wall jet domain on downstream development of the flow. The comparisons of flow characteristics simulated by the Reynolds stress turbulence model closure (Stress-omega, SWRSM) and experimental results indicate that this model may be considered reasonable for simulating the wall jet. The confined wall jet is further analyzed in a parametric study, with the results compared to the experimental data. The results indicate that the height and the width of the wind tunnel and the lip thickness of the jet nozzle have a great effect on the wall jet development. The top plate of the tunnel does not confine the development of the wall jet within 200b of the nozzle when the height of the tunnel is more than 40b (b is the height of jet nozzle). The features of the centerline flow in the mid plane of the 3D numerical model are close to those of the 2D simulated plane wall jet when the width of the tunnel is more than 20b.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.2
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• pp.77-85
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• 2000

Simulation of local external forcing and its response in the rotation table experiment has been investigated. Spatially-uniform external forcings have been applied in many experimental studies, however, based on the fact that the north-south distribution of the wind-stress curl and the existence of local maximum of the sea surface heat loss in the northern part of the East Sea, new method of combined effects of local forcings has been employed in separate experiments. Carefully designed local source or sink at the bottom of the cylindrical container can produce horizontal pressure gradient within the Ekman layer, and consequently the interior also attains the same pressure gradient that produces geostrophic interior circulation. In order to keep free surface during the local-surface cooling, a side-wall cooling method is suggested. For the various type of local forcing including the effects local cooling and the periodic change of local wind-stress curl, western-boundary flow in terms of its strength, position of separation from the boundary have been observed.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.10 no.1
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• pp.284-305
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• 1997

A Literatural study on the etiological factors, classification, prescription of hemorrhoids and hemorrhoids complicated by anal fistula following results were obtained. 1. The cause of hemorrhoids are long time sit, long time gate, overfatigue, overeating, imbalance of stool( constipation or diarrhea), pregnant fertility(overfatigue after childbirth, insufficiency of middle warmer energy), uncontrol sexual excess, pathgenic factors of wetness, heat, wind, dry, genetic cause, excess of anxiety, pile up of heat poison, weakness of entrails and viscera. The cause of hemorrhoid complicated by anal fistula are attack of external wind, heatness, dry, fire, wetness(pathgenic factors), inapporiate treatment and chronic disease, greasy diet, excess of anxiety, constipation, uncontrol sexual excess, obstacle of circulation of vital energy and blood on anal site. 2. Classification of hemorrhoids are female hemorrhoids, male hemorrhoids, pulse hemorrhoids, intestines hemorrhoids, vital energy hemorrhoids, wine hemorrhoids, blood hemonhoids, flowing hemorrhoids. Classification with other method are external hemorrhoids, internal hemorrhoids, mixed hemorrhoids, excrescence hemorrhoids, nipple homorrhoids. External hemorrhoids is classified of varicosis of hemorrhoidal vein, connective tissue form, thrombus form. Classification of hemorrhoid complicated by anal fistula are simple lower hemorrhoid, lower mixed hemorrhoid, deep hemorrhoid, outer of one hole hemorrhoid, a horseshoe hemorrhoids. Once more classificated of four are space of sphincter muscle form, penetration sphincter muscle form, upper of sphincter muscle form, outer of sphincter muscle form. 3. Therapy method of hermorrhoid and hemorrhoid complicated by anal fistula are internal method, fumigation method method, ointment, method of close with medicine, necrotizing method, hot medicated compress( gxternal method), injection, insertion, bind, (operation) and acupuncture therapy (the others method) 4. Herb medicine for many used of internal method are Scutellaria baikalensis George(黃芩), Coptis japonia Makino(黃連), Rehmania giutinosa Liboschitz ex Fischer & Meyer(生地黃), Poncirus trifoliata Refinesque(枳殼), Sanguisorba officinalis Linne(地楡), Sophora japonica L.(槐花), Cnidium officinale Makino (川芎), Astragalus membranaceus Bunge(황기), Angelica gigas Nakai (當歸). 5. Herb medicine for many used of fumigation are Schlechtendalia Chinesis J. Bell (五倍子), Artemisia Vulgaris L. var indica Maxim(艾葉), Poncirus trifoliata Refinesque (枳殼), Nepeta japonica Maximowicy(荊芥), And herb medicine for many used of ointment are Calomelas(輕粉), Alum(白礬), Boswellia carterii Birdwood(乳香), Os Draconis Fossilia Ossis Mastodi(龍骨).

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.5A
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• pp.657-664
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• 2008

Rain-wind induced cable vibration can cause the damages in the cable-stayed bridge due to very little inherent damping characteristics and low fundamental frequency. External Dampers attached to stay cables near anchorages have been shown to be effective means at short stay-cables. However, installation locations of external dampers are limited to a particular range due to aesthetic and practical reasons for very long stay-cables. A recent study by the authors showed that the stay-cable vibration system can perform better than the optimal passive viscous damper, thereby demonstrating its applicability in large cable-stayed bridges. This paper extends the previous study on the taut string representation of the cable by adding cable sag and inclination. The response of the proposed system compared to those of the cable with and without an external damper, and the movable anchorage system provides very effective mitigation of cable vibration. Cable damping ratio is seen to be remarkably reduced by movable anchorage system for a wide range of cable sag. This result shows that the sag effects of the proposed system should be considered.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.1
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• pp.115-120
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• 2011

The dynamic responses of a 5 MW wind turbine lifted by a floating crane with two elastic booms are analyzed. Dynamic equations of motions of a multibody system that consists of a floating crane, two elastic booms, and a wind turbine are derived. The six-degree-of-freedom (DOF) motions for the floating crane and the wind turbine are considered in the equations of motions. The hydrostatic force, the hydrodynamic force due to a regular wave, the mooring force, the wire rope force, and the gravitational force are considered as external forces. By solving the equations numerically, the dynamic responses of cargo are simulated. The simulation results are compared with those in the case of one elastic boom. Finally, the dynamic responses of the wind turbine lifted by the floating crane are analyzed under regular wave condition.

• Wind and Structures
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• v.15 no.4
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• pp.331-343
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• 2012

Thunderstorm downbursts are responsible for numerous structural failures around the world. The wind characteristics in thunderstorm downbursts containing vortex rings differ with those in 'traditional' boundary layer winds (BLW). This paper initially performs an unsteady-state simulation of the flow structure in a downburst (modelled as a impinging jet with its diameter being $D_{jet}$) using a computational fluid dynamics (CFD) method, and then analyses the pressure distribution on a solar updraft tower (SUT) in the downburst. The pressure field shows agreement with other previous studies. An additional pair of low-pressure region and high-pressure region is observed due to a second vortex ring, besides a foregoing pair caused by a primary vortex ring. The evolutions of pressure coefficients at five orientations of two representative heights of the SUT in the downburst with time are investigated. Results show that pressure distribution changes over a wide range when the vortices are close to the SUT. Furthermore, the fluctuations of external static pressure distribution for the SUT case 1 (i.e., radial distance from a location to jet center x=$D_{jet}$) with height are more intense due to the down striking of the vortex flow compared to those for the SUT case 2 (x=$2D_{jet}$). The static wind loads at heights z/H higher than 0.3 will be negligible when the vortex ring is far away from the SUT. The inverted wind load cases will occur when vortex is passing through the SUT except on the side faces. This can induce complex dynamic response of the SUT.