• 제목/요약/키워드: Heat Interaction

검색결과 565건 처리시간 0.029초

ACCURATE ESTIMATION OF GLOBAL LATENT HEAT FLUX USING MULTI-SATELLITE DATA

  • Tomita Hiroyuki;Kubota Masahisa
    • 대한원격탐사학회:학술대회논문집
    • /
    • 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
    • /
    • pp.14-17
    • /
    • 2005
  • Global latent heat flux data sets are crucial for many studies such as those related to air-sea interaction and climate variation. Currently, various global latent heat flux data sets are constructed using satellite data. Japanese Ocean Flux data sets with Use of Remote sensing Observations (J-OFURO) includes one of the satellite-derived global latent heat flux data (Kubota et aI., 2000). In this study, we review future development of J-OFURO global latent heat flux data set. In particular, we investigate usage of multi-satellite data for estimating accurate global latent heat flux. Accurate estimation of surface wind speeds over the global ocean is one of key factors for the improved estimation of global latent heat flux. First, we demonstrate improvement of daily wind speed estimation using multi-satellites data from microwave radiometers and scatterometers such as DMSP/SSMI, ERS/AMI, QuikSCAT/SeaWinds, AqualAMSR-E, ADEOS2/AMSR etc. Next, we demonstrate improvement of global latent heat flux estimation using the wind speed data derived from multi-satellite data.

  • PDF

평판 핀에서의 강제대류 열전달에 미치는 복사효과 (Radiative Effect on the Conjugated Forced Convection-Conduction Heat Transfer in a Plate Fin)

  • 손병진;민묘식;최상경
    • 대한기계학회논문집
    • /
    • 제14권2호
    • /
    • pp.453-462
    • /
    • 1990
  • The interaction of forced convection-conduction with thermal radiation in laminar boundary layer over a plate fin is studied numerically. The analysis is based on complete solution whereby the heat conduction equation for the fin is solved simultaneously with the conservation equations for mass, momentum and energy in the fluid boundary layer adjacent to the fin. The fluid is a gray medium and diffusion(Rosseland) approximation is used to describe the radiative heat flux in the energy equation. The resulting boundary value problem are convection-conduction parameter N$_{c}$ and radiation-conduction parameter m, Prandtl number Pr. Numerical results are presented for gases with the Prandtl numbers of 0.7 & 5 with values of N$_{c}$ and M ranging from 0 to 10 respectively. The object of this study is to provide the first results on forced convection-radiation interaction in boundary layer flow over a semi-infinite flay plate which can be used for comparisons with future studies that will consider a more accurate expression for the radiative heat flux. The agreement of the results from the complete solution presented by E. M. Sparrow and those from this paper for the special case of M=0 is good. The overall rate of heat transfer from the fin considering radiative effect is higher than that from the fin neglecting radiative effect. The local heat transfer coefficient with radiative effect is higher than that without radiative effect. In the direction from tip to base, those coefficients decrease at first, attain minimum, and then increase. The larger values of N$_{c}$ M, Pr give rise to larger fin temperature variations and the fin temperature without radiative effect is always higher than that with radiative effect.

2016년 1월 23일~25일에 발생한 서해안 대설 발달 메커니즘 분석 (Analysis of the West Coast Heavy Snowfall Development Mechanism from 23 to 25 January 2016)

  • 이재근;민기홍
    • 대기
    • /
    • 제28권1호
    • /
    • pp.53-67
    • /
    • 2018
  • This study examined the lake effect of the Yellow Sea which was induced by the Siberian High pressure system moving over the open waters. The development mechanism of the convective cells over the ocean was studied in detail using the Weather Research and Forecasting model. Numerical experiments consist of the control experiment (CTL) and an experiment changing the yellow sea to dry land (EXP). The CTL simulation result showed distinct high area of relative vorticity, convergence and low-level atmospheric instability than that of the EXP. The result indicates that large surface vorticity and convergence induced vertical motion and low level instability over the ocean when the arctic Siberian air mass moved south over the Yellow Sea. The sensible heat flux at the sea surface gradually decreased while latent heat flux gradually increased. At the beginning stage of air mass modification, sensible heat was the main energy source for convective cell generation. However, in the later stage, latent heat became the main energy source for the development of convective cells. In conclusion, the mechanism of the west coast heavy snowfall caused by modification of the Siberian air mass over the Yellow Sea can be explained by air-sea interaction instability in the following order: (a) cyclonic vorticity caused by diabatic heating induce Ekman pumping and convergence at the surface, (b) sensible heat at the sea surface produce convection, and (c) this leads to latent heat release, and the development of convective cells. The overall process is a manifestation of air-sea interaction and enhancement of convection from positive feedback mechanism.

Identification and Characterization of the Interaction between Heat-Shock Protein 90 and Phospholipase C-γ1

  • Kim, Su-Jeong;Kim, Myung-Jong;Kim, Yong;Si, Fu Chun;Ryu, Sung-Ho;Suh, Pann-Chill
    • BMB Reports
    • /
    • 제33권2호
    • /
    • pp.97-102
    • /
    • 2000
  • Phosphoinositide-specific phospholipase C-${\gamma}1$ (PLC-${\gamma}1$) is a pivotal mediator in the signal transduction cascades induced by many growth factors. Using a yeast two-hybrid system, heat-shock protein 90 (Hsp90) was identified as a PLC-${\gamma}1$-binding protein. A co-immunoprecipitation experiment, using anti-PLC-${\gamma}1$ antibody, demonstrated an in vivo interaction between Hsp90 and PLC-${\gamma}1$ in the NIH-3T3 cells. The interaction in NIH-3T3 was unaffected by the PDGF treatment, inducing phosphorylation and activation of PLC-${\gamma}1$. Direct interaction between Hsp90 and PLC-${\gamma}1$ was confirmed by in vitro binding experiments using purified Hsp90 and PLC-${\gamma}1$. Furthermore, Hsp90 increased the $PIP_2$-hydrolyzing activity of PLC-${\gamma}1$ up to 2-fold at $0.1{\mu}M$ in vitro. Taken together, we show for the first time, the interaction of PLC-${\gamma}1$ with Hsp90, both in vivo and in vitro. We suggest that Hsp90 may play a role in PLC-${\gamma}1$-mediated signal transduction.

  • PDF

상호작용하는 대향류 메탄 및 수소 예혼합화염에서 당량비 조건에 따른 상호작용 모드 변화 (Interaction Mode Change According to the Equivalence Ratios in the Interacting Methane and Hydrogen Counterflow Premixed Flames)

  • 박지웅;오창보
    • 한국연소학회:학술대회논문집
    • /
    • 한국연소학회 2012년도 제44회 KOSCO SYMPOSIUM 초록집
    • /
    • pp.13-16
    • /
    • 2012
  • The interaction between methane and hydrogen premixed flames with the different equivalence ratio and global strain rate was investigated numerically in one-dimensional counterflow field. The OPPDIF code and GRI-v3.0 were used to simulate the interacting flames. Overall trends in the maximum heat release rates of $CH_4{^-}$ and $H_2$-side flame were examined with the variation of $a_g$. The interaction mode of the flames were classified according to the equivalence ratios and Lewis numbers of each flame and global strain rate.

  • PDF

와류발생기의 가진 주파수에 의한 열전달 향상 (Heat Transfer Enhancement by an Oscillating Frequency of Vortex Generator)

  • 방창훈;김정수;예용택
    • 한국안전학회지
    • /
    • 제21권2호
    • /
    • pp.7-14
    • /
    • 2006
  • A Problem of low-velocity forced convection in a channel flow with heated wall is of practical importance and widely considered in the design of devices such as heat exchangers, and electronic equipments. Therefore, there is an urgent need for improving heat transfer performance of heated wall in the channel. In the present study, an oscillating vortex generator method is proposed to enhance the heat transfer in a channel. In this method, a rectangular bars are set in the upstream of heated region of the channel. The bars are forced to oscillate normal to the inflow, and then actively and largely generates transverse vortices behind the bars. As a result, this apparatus can enhance the heat transfer rates remarkably. Because of the interaction between the flow and oscillating bars, the variations of the flow and thermal fields become time-dependent state.

Surface Heat Flux and Oceanic Heat Advection in Sendai Bay

  • Yang Chan-Su;Hanawa Kimio
    • 대한원격탐사학회지
    • /
    • 제22권1호
    • /
    • pp.11-24
    • /
    • 2006
  • Coastal sea surface temperature (CSST) and meteorological data from January through December 1995 are used to estimate the net surface heat flux and heat content for Sendai Bay. The average annual surface heat flux in the area north of the bay is estimated to be $+35Wm^{-2}$, whereas the southwestern area is estimated to be $+56Wm^{-2}$. Therefore, the net surface heat flux shows a net gain of heat over the whole bay. The largest heat gain occurs near Matsukawaura, where the strong Kuroshio/Oyashio interaction produces anomalously cold SST and wind is more moderate than in other regions of Sendai Bay over most of the year. The lowest heat gain occurs around Tashiro Island, where the temperature difference between air and sea surface is lower and wind is stronger. The heat budget shows that both surface forcing and horizontal advection are potentially important contributors to the seasonal evolution of CSST in the bay. From the A VHRR and SeaWiFS data, it is found that offshore conditions between the bay and Eno Island are different due to the presence of the Ojika Peninsula. It is also shown that the temporal behaviors of SSTs in the bay are closely connected with the air-sea heat flux and offshore conditions.

SNG/Air 예혼합 화염들의 하류상호작용에 있어서 화염 소화 거동에 관한 연구 (A Study on Flame Extinction Behavior in Downstream Interaction between SNG/Air Premixed Flames)

  • 심근선;이기만
    • 한국연소학회지
    • /
    • 제21권4호
    • /
    • pp.48-60
    • /
    • 2016
  • Experimental and numerical studies were conducted to investigate flame behaviors near flammable limits for downstream-interacting SNG-air premixed flames in a counter-flow configuration. The SNG fuel consisted of a methane, a propane, and a hydrogen with volumetric ratios of 91, 6, and 3%, respectively. The most appropriate priority for some reliable reaction mechanisms examined was given to the mechanism of UC San diego via comparison of lean extinction limits attained numerically with experimental ones. Flame stability map was presented with a functional dependencies of lower and upper methane concentrations in terms of global strain rate. The results show that, at the global strain rate of $30s^{-1}$, lean extinction boundary is slanted while rich extinction one is relatively less inclined because of the dependency of such extinction boundary shapes on deficient reactant Lewis number governed by methane mainly. Further increase of global strain rate forces both extinction boundaries to be more slanted and to be shrunk, resulting in an island of extinction boundary and subsequently one flame extinction limit. Extinction mechanisms for lean and rich, symmetric and asymmetric extinction boundary were identified and discussed via heat losses and chemical interaction.