• Title/Summary/Keyword: Wake pattern

Search Result 98, Processing Time 0.025 seconds

Development of a Family Pattern Appraisal to Guide a Rogerian Nursing Practice (Rogers 이론에 근거한 가족양상 사정지침개발)

  • 이광옥;한영란;김희정
    • Journal of Korean Academy of Nursing
    • /
    • v.25 no.4
    • /
    • pp.751-773
    • /
    • 1995
  • We, clinical nurse specialists practising and guiding student practice in a Community health nursing clinic, wanted to develop a family pattern appraisal consistent with Rogers' conceptual system, the nursing model guiding our practice. We use Rogers' model because it is harmonious with the traditional Korean view of the one human, natural and cosmic world. The purpose of our research was to contribute to science - based nursing practice, not only, one helpful model, but also a model of how to use, in guiding practice, a conceptual system which reflects nurse practitioners' philosophy of nursing, is intellectually satisfying, and enriches meaning in daily nursing life. The research objectives were to review the literature on Rogers' model and analyse it according to Kim's five - level analytical framework, to explore Rogers' definition of family, to review appraisals based on Rogers' model, and to develop a family appraisal which is culturally appropriate for use in our community. This work including the use of the appraisal and its refinement with families in our practice which was done during 1994 and 1995, in Seoul, in the Capital of the Republic of Korea. At the highest level of analysis, Rogers conceptual system emphasizes acausality and multidimentional meaning ; the world view is characterized by process, movement and wholeness. The epistemology Is one of holism and the knowledge base includes all forms of experience, from sensory to mystical, objective, and subjective. At the metaparadigm level, nursing focuses on the unitary human being and the environment. At the level of nursing philosophy, the model identifies human being, nursing, nurse, and illness and health. At the paradigm level the model assumes the irriducibility of the human to parts, noncausality and continual change. Rogers' practice methodology consists of pattern manifestation appraisal and deliberative mutual patterning. Under-standing patterns and patterning of people is the key to helping them achieve their potential. At the theory level, the basic assumptions, key concepts, and homeodynamic principles were identified. Rogers states the family energy field is an undividable, four-dimensional negentropic energy field which is in a larger envircinmental field show-ing such characteristics as cannot be predicted by knowledge of individual family members. Based on the word of Rogers scholars, we chose Rogers' correlates of patterning to understand the family unit as a whole-frequency, rhythms, motion, time perception, sleeping-waking beyond waking, pragmatic -imaginative-visionary to develop the appraisal. We, also used some of Barrel's (1988) criteria including interpersonal network and professional health care access and use, and Cordon's (1982) criteria including self perception - self concept modified to fit the family. Our family Pattern appraisal included 1. Influencirg data, 2. Professional health care access and use, 3. Family self perception-self concept, 4. Family interpersonal network, 5. Sleep-wake-be-yond waking, 6. Pragmatic-imaginary-visionary, 7. Family frequency and rhythm, 8. Family motion, 9. Family time perception. The appraisal was used with four families and modified to eliminate overlap and to make it possible for the family member to express themselves more easily. We plan to gain more experience with the appraisal toward further development of the tool.

  • PDF

Effect of tip configuration of an oil fence on wake structure behind the fence (오일펜스의 tip 형상이 후류유동에 미치는 영향에 관한 연구)

  • Koh, Min-Seok;Lee, Sang-Joon;Lee, Choung-Mook;Chung, Sang-Kook
    • Proceedings of the KSME Conference
    • /
    • 2001.06e
    • /
    • pp.772-776
    • /
    • 2001
  • The flow structures of turbulent shear layer behind oil fences with different tip configurations were investigated experimentally using flow visualization and PIV velocity field measurement. An oil fence was installed in a circulating water channel and the flow structure around the fence tip was mainly analyzed in this experiment. The four tip configurations tested in this experiment are knife edge; semi-circle edge, circular edge and rectangular edge. The 300 instantaneous velocity fields were measured using the single-frame PIV system and they were ensemble averaged to give the mean velocity field and spatial distribution of turbulent statistics. Free stream velocity was fixed at 10ms/sec and the corresponding Reynolds number based on the fence height was Re=4000. As a result, for the oil fence with rectangular edge, the streamwise velocity component was decreased. On the other hand it was increased for the oil fence with circular edge. For all four fences tested in this study, general flow pattern of the lower shear layer is analogous but the upper layer shows difference depending on the tip configurations. The oil fence with circular edge has more diffusive upper shear layer than that of the others. The shear layer of the oil fence with rectangular edge has relatively thin thickness. The oil fence with circular edge was found to be proper shape for tandem fence.

  • PDF

Experimental Investigation on the Gap Cavitation of Semi-spade Rudder (Semi-spade 타의 간극 캐비테이션에 대한 실험적 연구)

  • Paik, Bu-Geun;Kim, Kyung-Youl;Ahn, Jong-Woo;Kim, Yong-Soo;Kim, Sung-Pyo;Park, Je-Jun
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.43 no.4 s.148
    • /
    • pp.422-430
    • /
    • 2006
  • The horn and movable parts around the gap of the conventional semi-spade rudder are visualized by high speed CCD camera with the frame rate of 4000 fps (frame per second) to study the unsteady cavity pattern on the rudder surface and gap. In addition, the pressure measurements are conducted on the rudder surface and inside the gap to find out the characteristics of the flow behavior. The rudder without propeller wake is tested at the range of $1.0{\leq}{\sigma}_v\;1.6$ and at the rudder deflection angle of $-8{\leq}{\theta}{\leq}10^{\circ}$. The time resolved cavity images are captured and show strong cavitation around the rudder gap in all deflection angles. As the deflection angle gets larger, the flow separated from the horn surface increases the strength of cavitation. The accelerated flow along the horn decreases its pressure and the separated flow from the horn increases the pressure abruptly. The pressure distribution inside the gap reveals the flow moving from the pressure to suction side. In the negative deflection angle, the turning area on the movable part initiates the flow separation and cavitation on it.

Numerical Investigation of Flow-pattern and Flow-induced Noise for Two Staggered Circular Cylinders in Cross-flow by LBM

  • Kim, Jeong-Whan;Oh, Sae-Kyung;Kang, Ho-Keun
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.32 no.1
    • /
    • pp.82-93
    • /
    • 2008
  • The flowfield behind two cylinders and flow-induced noise generated from the cylinders in various arrangement are numerically investigated based on the finite difference lattice Boltzmann model with 21 velocity bits. which is introduced a flexible specific heat ${\gamma}$ to simulate diatomic gases like air. In an isolated cylinder with two type of mesh. some flow parameters such as Strouhal number $S_t$ and acoustic pressure ${\Delta}p$ simulated from the solution are given and quantitatively compared with those provided the previous works. The effects of the center-to-center pitch ratio $L_{cc}/d=2.0$ in staggered circular cylinders as shown in Fig. 1 and angles of incidence ${\alpha}=30^{\circ}(T_{cc}/d=0.5)$, $45^{\circ}(T_{cc}/d =0.707)$ and $60^{\circ}\;(T_{cc}/d=0.866)$, respectively, are studied. Our analysis focuses on the small-scale instabilities of vortex shedding, which occurs in staggered arrangement. With the results of drag $C_d$ and lift $C_l$ coefficients and vorticity contours. the mechanisms of the interference phenomenon and its interaction with the two-dimensional vortical structures are present in the flowfields under $Re\;{\le}\;200$. The results show that we successively capture very small pressure fluctuations, with the same frequency of vortex shedding, much smaller than the whole pressure fluctuation around pairs of circular cylinders. The upstream cylinder behaves like an isolated single cylinder, while the downstream one experiences wake-induced flutter. It is expected that, therefore, the relative position of the downstream cylinder has significant effects on the flow-induce noise, hydrodynamic force and vortex shedding characteristics of the cylinders.

The Visualization of the Flowfield around Three Circular Cylinders in the Tandem Arrangement by the PIV (PIV에 의한 직렬배열 상태에 놓인 3원주 주위의 유동장 가시화)

  • Ro, Ki-Deok;Jang, Dong-Hyu;Bae, Hung-Sub;Kim, Won-Cheol
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.35 no.2
    • /
    • pp.264-270
    • /
    • 2011
  • The Characteristics of the flowfield around three circular cylinders in tandem arrangement was investigated by PIV. Strouhal numbers, vorticity, velocity vectors and velocity profiles were observed at centre-to-centre space ratios of P/D=1.25~3.75, and Reynolds number of Re=$3.0{\times}10^3{\sim}5.0{\times}10^3$. As the results the Strouhal numbers measured in the rear region of 3rd the cylinder were distinguished three kind of regions with the space ratios and The flow pattern in the wake of each cylinder was different according to these regions. The time averaged flow at region of each cylinder was almost stagnated and the size of the stagnated region was small in order of 1st, 2nd and 3rd cylinder. The direction of vortex at the front and rear region of 2nd cylinder was opposed each other with the small difference(${\alpha}= {\pm}5^{\circ}$) of the attack angle ${\alpha}$.

Computational Study of the Scale Effect on Resistance and Propulsion Performance of VLCC (대형 유조선의 저항 및 추진성능에 대한 축척효과의 수치적 연구)

  • Choi, Jung-Eun;Kim, Jung-Hun;Lee, Hong-Gi
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.48 no.3
    • /
    • pp.222-232
    • /
    • 2011
  • This article examines the scale effect of the flow characteristics, resistance and propulsion performance on a 317k VLCC. The turbulent flows around a ship in both towing and self-propulsion conditions are analyzed by solving the Reynolds-averaged Navier-Stokes equation together with the application of Reynolds stress turbulence model. The computations are carried out in both model- and full-scale. A double-body model is applied for the treatment of free surface. An asymmetric body-force propeller is used. The speed performances including resistance and propulsion factors are obtained from two kinds of methods. One is to analyze the computational results in model scale through the revised ITTC' 78 method. The other is directly to analyze the computational results in full scale. Based on the computational predictions, scale effects of the resistance and the self-propulsion factors including form factor, thrust deduction fraction, effective wake fraction and various efficiencies are investigated. Scale effects of the streamline pattern, hull pressure and local flow characteristics including x-constant sections, propeller and center plane, and transom region are also investigated. This study presents a useful tool to hull-form and propeller designers, and towing-tank experimenters to take the scale effect into consideration.

Effects of Light Pollution from Mobile Digital Devices on Sleep and Circadian Rhythms (모바일 디지털 기기로 인한 빛공해가 수면과 일주기 리듬에 미치는 영향)

  • Lee, Youn-Jung;Cho, Chul-Hyun;Lee, Heon-Jeong
    • Sleep Medicine and Psychophysiology
    • /
    • v.27 no.1
    • /
    • pp.1-7
    • /
    • 2020
  • Mobile digital devices are very familiar and useful devices in the daily life of modern people, and are used for various tasks such as communication, reading, writing, and playing media. As the use of mobile digital devices has become more prevalent, user time has also been increasing. In particular, the number of people who use digital devices before sleep is growing. The light pollution associated with these devices is classified into four categories: urban sky glow, glare, light trespass, and clutter. The pattern in which modern people use digital devices corresponds to light pollution caused by light trespass and clutter from light exposure to artificial light at night. The light pollution caused by digital devices can cause melatonin secretion suppression, delayed sleep onset, reduction of sleepiness before bedtime, and periodic rhythm and cognitive function disturbances. In addition, a study of children and adolescents showed there may be disturbances in the sleep-wake cycle and circadian rhythm, deterioration of sleep quality, and daytime fatigue due to light pollution caused by artificial light at night from mobile digital devices. A multi-faceted research effort is also necessary to investigate the healthy use of mobile digital devices based on research evidence and insights with an accurate evaluation of the influence of mobile digital devices as a form of light pollution.

Visualization Study on the Phase Difference of a Dragonfly Type Wing (잠자리 유형 날개의 위상차에 대한 가시화 연구)

  • Kim Hyun Seak;Kim Song Hak;Chang Jo Won
    • Journal of the Korean Society of Propulsion Engineers
    • /
    • v.8 no.4
    • /
    • pp.43-54
    • /
    • 2004
  • A visualization study was carried out to investigate the effects of phase difference qualitatively by examining wake pattern on the phase difference of a dragonfly type wing model. The model was built with scaled-up, flapping wings composed of a paired wing with fore- and hind-wings in tandem that mimick the wing form of a dragonfly. The present study was conducted by using the smoke-wire technique and an electronic device below the tandem wings was mounted to find the exact wing position angles. Uncertainties in wing position angle are about $\pm$$1.0^{\cire}$ and instantaneous wing positional angle varies from $-16.5^{\cire}$ to $+22.8^{\cire}$. The tests were made at phase differences between the fore-wing and hind-wing at $0^{\cire}$, $90^{\cire}$, $180^{\cire}$ and $270^{\cire}$. The results show that Karman vortex structures were produced at phase differences of $90^{\cire}$, $180^{\cire}$ and $270^{\cire}$, but Karman vortex structures were not observed at the phase difference of $0^{\cire}$.

Association between cold-heat symptoms and sleep disturbances according to the Sasang constitution: a cross-sectional community study

  • Hyun, Min Kyung;Yoshino, Tetsuhiro
    • Journal of Society of Preventive Korean Medicine
    • /
    • v.26 no.1
    • /
    • pp.59-74
    • /
    • 2022
  • Objectives : Evidence supporting the cold-heat symptom and sasang constitution type, which are diagnostic items of traditional Korean medicine, is needed to manage sleep disturbances, which is a typical symptom of mibyeong (subhealth). This study examined the association between each cold-heat symptom and sleep disturbances according to each sasang constitution type. Methods : This research was a cross-sectional study of 5,793 subjects from the Korean Medicine Data Center (KDC) community cohort survey. The association between each cold-heat symptom and sleep disturbances was analyzed by logistic regression analysis adjusted for several demographic variables. Subgroup analysis was then performed for each type of sasang constitution. Results : The soeum and soyang types were 1.53 and 1.26 times more likely to have sleep disturbances than the taeum type. Sleep disturbances were associated with 'coldness of the abdomen', 'watery mouth' in the cold domain items, and 'body feverishness', 'flushed face and eye', 'thirst', and 'scanty dark urine' in the heat domain items. The soeum and soyang types were 1.55 and 1.39 times more likely to sleep less than five hours per night than the taeeum type. In addition, the associations of those showed a different pattern for each sasang constitution type. Conclusions : Sleep disturbances are associated with specific cold-heat symptoms, and the associated cold-heat symptoms differ according to the sasang constitution type. These results may help traditional medicine specialists select customized interventions for patients with sleep disturbances.

Experimental Study on the Unsteady Flow Characteristics for the Counter-Rotating Axial Flow Fan

  • Cho, L.S.;Lee, S.W.;Cho, J.S.;Kang, J.S.
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2008.03a
    • /
    • pp.790-798
    • /
    • 2008
  • Counter-rotating axial flow fan(CRF) consists of two counter-rotating rotors without stator blades. CRF shows the complex flow characteristics of the three-dimensional, viscous, and unsteady flow fields. For the understanding of the entire core flow in CRF, it is necessary to investigate the three-dimensional unsteady flow field between the rotors. This information is also essential to improve the aerodynamic characteristics and to reduce the aerodynamic noise level and vibration characteristics of the CRF. In this paper, experimental study on the three-dimensional unsteady flow of the CRF is performed at the design point(operating point). Flow fields in the CRF are measured at the cross-sectional planes of the upstream and downstream of each rotor using the $45^{\circ}$ inclined hot-wire. The phase-locked averaged hot-wire technique utilizes the inclined hot-wire, which rotates successively with 120 degree increments about its own axis. Three-dimensional unsteady flow characteristics such as tip vortex, secondary flow and tip leakage flow in the CRF are shown in the form of the axial, radial and tangential velocity vector plot and velocity contour. The phase-locked averaged velocity profiles of the CRF are analyzed by means of the stationary unsteady measurement technique. At the mean radius of the front rotor inlet and the outlet, the phase-locked averaged velocity profiles show more the periodical flow characteristics than those of the hub region. At the tip region of the CRF, the axial velocity is decreased due to the boundary layer effect of the fan casing and the tip vortex flow. The radial and the tangential velocity profiles show the most unstable and unsteady flow characteristics compared with other position of rotors. But, the phase-locked averaged velocity profiles of the downstream of the rear rotor show the aperiodic flow pattern due to the mixture of the front rotor wake period and the rear rotor rotational period.

  • PDF