Three-dimensional time-evolving plume-slab interaction for the generation of the Abukuma adakite, Northeast Japan

Lee, C.,Lim, C. International Association for Gondwana Research 2016 GONDWANA RESEARCH Vol.38 No.-

The pulse-like eruption of the Abukuma adakite in Northeast Japan at ~16Ma has previously been explained by localized and short-term (pulse-like) plume-slab interaction, where the plume ascended through a slab neck that developed in the subducted Pacific plate. However, because previous research was based on a two-dimensional (2D) model, considering the three-dimensional (3D) aspects of the plume blob that was injected into the corner of the mantle wedge was impossible, and its effects on the plume-slab interaction remained unknown. In this study, we conducted a series of 3D kinematic-dynamic numerical subduction models to evaluate the effects of the 3D plume blob on the partial melting of the subducted oceanic crust by varying the duration and size of the plume blob. Our 3D model shows two major outcomes in contrast to 2D model. First, a 3D plume blob with a duration of 5Myr, a thickness of 60km, and a wide range of widths from 80 to 200km is correlated with the pulse-like eruption of the Abukuma adakite, compared to the longer and much thicker 2D plume blob, which has a duration of 10Myr and a thickness of 70km. This result indicates that the 2D model overestimated the duration and thickness of the plume blob compared to those from the 3D model. Second, a 'trough' of lower slab surface temperatures developed by 3D plume-slab interaction, which intensified the temperature contrasts between the plume-slab contacting zone and the adjacent slab surface. The vigorous injection of the low viscosity plume blob into the corner of the mantle wedge generated lateral (trench-parallel) and returning mantle flow, which impeded the incoming corner flow from reaching the slab surface and produced the troughs of lower slab surface temperatures near the plume-slab contacting zone. The 3D plume-slab interaction thus has an important implication for the Quaternary arc volcanism and the 3D mantle flow in Northeast Japan.

천음속 영역에서 과소 팽창 화염이 종안정성에 미치는 영향에 관한 연구

정석영(Suk Young Jung),윤성준(Sung Joon Yoon) 한국항공우주학회 2004 韓國航空宇宙學會誌 Vol.32 No.8

??화염에 의한 종방향 공력 특성의 변화를 해석하기 위하여 고형 화염 모형을 이용한 풍동 시험과 고형 회-염 모형과 제트 화염 모델을 이용한 난류 유동 수치 해석을 실시하였다. 화염 경계면 근사 기법을 이용하여 산출한 형상을 본떠 화염 모형을 제작하였으며 제트 화염 모델링 기법을 이용하여 공기와 실제 화염의 열역학적 차이로 인한 오차를 보정한 공기 제트 화염을 생성하였다. 화염과 외부 공기의 간섭에 대해 난류 모델 간의 비교를 통하여 정확도와 격자 의존성 등에서 Spalart-Allmaras 모델이 좋은 결과를 주었다. 수치 해석을 통하여 고형 화염 모형과 제트 화염의 차이를 분석하였으며, 실제 비행 시험에 대한 화염 영향을 분석하기 위하여 연소실과 대기 압력 비와 레이놀즈수에 따른 변화를 해석하였다. Exhaust plume effects on longitudinal aerodynamics of missile were investigated by wind tunnel tests using a solid plume simulator and CFD analyses with both the solid plume and air jet plumes. Approximate plume boundary prediction technique was used to produce the outer shape of the solid plume, and chamber conditions and nozzle shapes of the air jet plumes were determined through plume modeling technique to compensate the difference in thermodynamic properties between air and real plume. From comparisons among turbulence models in case of external flow interaction with the air jet plume, Spalart-Allmaras model turned out to give accurate result and to be less grid-dependent. Effects induced by the plume were evaluated through the computations with Spalart-Allmaras turbulence model and the air jet plume to account for various ratios of chamber and ambient pressure and Reynolds number under the flight test condition.

Intracontinental mantle plume and its implications for the Cretaceous tectonic history of East Asia

Ryu, In-Chang,Lee, Changyeol Elsevier 2017 Earth and planetary science letters Vol.479 No.-

<P><B>Abstract</B></P> <P>A-type granitoids, high-Mg basalts (e.g., picrites), adakitic rocks, basin-and-range-type fault basins, thinning of the North China Craton (NCC), and southwest-to-northeast migration of the adakites and I-type granitoids in southern Korea and southwestern Japan during the Cretaceous are attributed to the passive upwelling of deep asthenospheric mantle or ridge subduction. However, the genesis of these features remains controversial. Furthermore, the lack of ridge subduction during the Cretaceous in recently suggested plate reconstruction models poses a problem because the Cretaceous adakites in southern Korea and southwestern Japan could not have been generated by the subduction of the old Izanagi oceanic plate. Here, we speculate that plume-continent (intracontinental plume-China continent) and subsequent plume-slab (intracontinental plume-subducted Izanagi oceanic plate) interactions generated the various intracontinental magmatic and tectonic activities in eastern China, Korea, and southwestern Japan. We support our proposal using three-dimensional numerical models: 1) An intracontinental mantle plume is dragged into the mantle wedge by corner flow of the mantle wedge, and 2) the resultant channel-like flow of the mantle plume in the mantle wedge apparently migrated from southwest to northeast because of the northeast-to-southwest migration of the East Asian continental blocks with respect to the Izanagi oceanic plate. Our model calculations show that adakites and I-type granitoids can be generated by increased slab-surface temperatures because of the channel-like flow of the mantle plume in the mantle wedge. We also show that the southwest-to-northeast migration of the adakites and I-type granitoids in southern Korea and southwestern Japan can be attributable to the opposite migration of the East Asian continental blocks with respect to the Izanagi oceanic plate. This correlation implies that an intracontinental mantle plume existed in eastern China during the Cretaceous and that the mantle plume was entrained into the mantle wedge as a channel-like flow. An intracontinental mantle plume can explain the adakitic rocks, A-type granitoids, high-Mg basalts, and basin-and-range-type fault basins distributed in eastern China. Thus, the mantle plume and its interaction with the overlying continent and subducting slab through time plausibly explain the Cretaceous tectonic history of East Asia.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cretaceous intracontinental and arc magmatism in East Asia is re-evaluated. </LI> <LI> 3-D numerical model shows that arc magmatism requires intracontinental mantle plume. </LI> <LI> NE–SW plate motion resulted in SW–NE migration of intracontinental and arc magmatism. </LI> </UL> </P>

Evaluation of CO₂ plume migration and storage under dip and sinusoidal structures in geologic formation

Han, Weon Shik,Kim, Kue-Young Elsevier 2018 Journal of petroleum science & engineering Vol.169 No.-

<P><B>Abstract</B></P> <P>A series of numerical simulations were conducted to explore the frontal speed of the CO<SUB>2</SUB> plume and residence time in the formation preserving the dipping and sinusoidal caprock. For this purpose, we generated various permutations of 2-D numerical models where the contact boundary between the caprock and targeted formation was simplified with the idealized sinusoidal function. Three parameters such as dip, amplitude, and wavelength were chosen to analyze how the dipping and sinusoidal structure could affect the frontal speed of CO<SUB>2</SUB> plume. Subsequently, the study was expanded to understand the effect of caprock permeability and the heterogeneity preserved in the storage formation.</P> <P>Simulation results under the condition of dipping caprock (2°–10°) indicated that the relationship between the migration distance of the CO<SUB>2</SUB> plume front and time followed the linear trends. Among the chosen sensitivity parameters of dip, amplitude, and wavelength, the speed of the CO<SUB>2</SUB> plume front was the most sensitive to the caprock dip, but the stored CO<SUB>2</SUB> mass varied the most significantly with the amplitude. In addition, when the caprock permeability increased, certain amounts of CO<SUB>2</SUB> escaped to the caprock, resulting in a retardation of the CO<SUB>2</SUB> plume. Similarly, in the sensitivity studies of dip, wavelength, and amplitudes, more CO<SUB>2</SUB> leaked to the caprock corresponded to smaller frontal speed of CO<SUB>2</SUB> plume. Finally, the increase in permeability heterogeneity of the targeted formation decreased the sharpness of CO<SUB>2</SUB> plume front while the mean arrival time of the plume front was relatively consistent.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Migration distance of CO<SUB>2</SUB> plume followed the linear trends under the dipping caprock. </LI> <LI> CO<SUB>2</SUB> mass varied the most significantly with the amplitude of the caprock. </LI> <LI> When the caprock k was increased, CO<SUB>2</SUB> plume front was retarded. </LI> <LI> Increase in k heterogeneity decreased the sharpness of CO<SUB>2</SUB> front. </LI> </UL> </P>

Analysis of the IR Signature and Radiative Base Heating from a Supersonic Solid Rocket Exhaust Plume

구본찬,Man Young Kim,백승욱 한국항공우주학회 2019 International Journal of Aeronautical and Space Sc Vol.20 No.2

The plume flow and radiative base heating of a solid rocket have been important factors for rocket survivability in the modern battlefield, in which the standard of technology determines the dominant position. To enhance rocket survivability and reduce base heating, infrared (IR) signatures emitted from an exhaust plume should be determined. In this work, therefore, IR signatures and radiative base heating characteristics in the plumes exhausted from a solid rocket operating at Mach number of 1.6 and altitudes of 5 km and 10 km, respectively, are numerically examined to find the physics related to the plume flow and radiative characteristics. The plume flow and radiative characteristics are obtained using a pre-conditioning method and weighted sum of gray gases model (WSGGM) coupled with finite volume method for radiation, respectively, and the IR signature at each location is post-processed with the narrow band-based WSGGM after plume fields are developed. After validating models adopted in this work by comparing with other solutions, the plume flow field, IR signature, and radiative base heating characteristics are investigated by changing such various parameters as altitude and particle concentrations in the exhaust plume. As a result, it is found that the particular wavelength IR signature level has high spectral characteristics because of CO2 and H2O behaviors in the plume, and the radiative heat flux coming into the base plane decreases with higher flight altitude and longer distance from the nozzle exit.

낙동강 하구에서 담수 유입에 따른 연안 클로로필-a 증가 : 낙동강의 육상-해양 coupling 패턴 분석

김수현,안순모 한국해양학회 2021 바다 Vol.26 No.2

Since terrestrial input plays a major role in coastal primary production, an understanding of land-ocean coupling (LOC) is key to understand coastal ecological changes. In this study, the LOC has been classified into three stages (i.e., the baseflow, plume event and residual flow). In order to characterize its pattern in Nakdong River estuary, multi-platform data were obtained from remote sensing (geostationary ocean color image (GOCI)), in-situ measurement (marine environment information system (MEIS)), on-site measurement (discharge data and meteorological data). The MEIS data were grouped into three stages of LOC using principal component analysis (PCA), and the LOC (2013 ~ 2018) was examined at each stage using multi-platform data. In the Nakdong River estuary, the maximum value of chlorophyll-a (chl-a) was unexpectedly appeared during the plume event. It is assumed that there was no significant increase in turbidity, expected during the typical plume event, together with the weak flushing effect, caused the enhanced phytoplankton growth. Compared with other estuaries, LOC is common in estuaries affected by freshwater inflow, but LOC has different pattern depending on the size of the plume. While estuaries that form small plumes of about 10 km (low freshwater discharge and weak flushing effect) observed high chl-a in the plume event because the phytoplankton can response to the increased nutrient more rapidly. estuaries that form large plumes of more than 100 km est (high freshwater discharge and strong flushing effect) follow the typical LOC pattern conceptualized in this study (high chl-a in the residual flow) 담수를 통해 유입되는 육상 기원 물질은 연안 일차 생산을 제어하는 주요 요소이므로 육상-해양 coupling을 파악하는 것은 연안 생태변화를 이해하는데 중요하다. 본 논문에서는 육상-해양 coupling 양상을 시간에 따라 세 단계(Base flow, Plume event, Residual flow) 로 구분하여 개념화하였고, 낙동강 하구에서 각 양상의 출현을 확인하기위해 다양한 플랫폼에서 측정된 자료를 사용하여 분석하였다. 사용된 자료는 원격 탐사 측정 자료(Geostationary Ocean Color Image; GOCI), 현장 실측 자료(Marine Environment Information System; MEIS), 연속 측정 자료(유량 자료, 기상 자료)로 구분될 수 있다. 주성분분석을 통해 MEIS 자료를 육상-해양 coupling의 세 단계로 구분하였고, 이 구분을 2013-2018년 동안의 여타 자료에 적용하여 단기간 육상-해양 coupling 양상을 살펴보았다. 낙동강 하구에서는 예상과는 달리 Plume event때 Chlorophyll-a (Chl-a) 최대값이 나타났다. 이는 담수 증가에도 탁도 증가는 크지 않았고, 플러싱효과도 약해 식물플랑크톤이 증가 할 수 있는 여건이 조성되었기 때문으로 분석되었다. 육상-해양 coupling을 기반으로 여러 하구들과 비교해보았을 때 육상-해양 coupling은 담수 유입에 영향을 받는 하구에서 흔한 현상이나 하구에서 형성되는 플룸 크기에 따라 육상-해양 coupling이 다르게 나타났다. 낙동강 하구처럼 작은 플룸(~10 km 규모) 이 형성되는 하구에서는 식물플랑크톤의 즉각적인 반응으로 인해 Plume event 단계에 Chl-a 최댓값이 나타나는 반면, ~100 km 이상의 큰 플룸이 형성되는 하구(담수 배출이 크고, 플러싱이 강한 곳)에서는 본 연구에서 개념화한 육상-해양 coupling 양상(Residual flow 때 Chl-a 최대)을 따르는 것으로 나타났다.

First Simultaneous Visualization of SO₂ and NO₂ Plume Dispersions using Imaging Differential Optical Absorption Spectroscopy

Lee, Hanlim,Noh, Youngmin,Kwon, Soonchul,Hong, Hyunkee,Han, Kyung-Soo Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.4

Imaging Differential Optical Absorption Spectroscopy (Imaging-DOAS) has been utilized in recent years to provide slant column density (SCD) distributions of several trace gas species in the plume. The present study introduces a new method using Imaging-DOAS data to determine two-dimensional plume structure from the plume emissions of power plant in conditions of negligible aerosol effects on radiative transfer within the plume. We demonstrates for the first time that two-dimensional distributions of sulfur dioxide ($SO_2$) and nitrogen dioxide ($NO_2$) in power plant emissions can be determined simultaneously in terms of SCD distribution. The $SO_2$ SCD values generally decreased with increasing distance from the stack and with distance from the center of the plume. Meanwhile, high $NO_2$ SCD was observed at locations several hundred meters away from the first stack due to the ratio change of NO to $NO_2$ in NOx concentration, attributed to the NO oxidation by $O_3$. The results of this study show the capability of the Imaging-DOAS technique as a tool to estimate plume dimensions in power plant emissions.

Plume의 주기성이 연층형성에 미치는 영향

한용식,김명배,오광철,신현동 한국화재소방학회 2002 한국화재소방학회논문지 Vol.16 No.2

ON-OFF 제트를 사용하여 plume의 주기성이 천장아래에 형성되는 연층에 미치는 정성적인 영향을 파악하였다. 사용된 연기는 가열에 의해 증발된 kerosene 입자를 섞은 질소가스이다. Laser sheet에 의해 산란된 유동장의 순간 상들은 디지털 비디오 카메라에 의해 녹화되었다. ON-OFF 제트와 연속제트의 연층형성 과정을 비교하므로서 화원근처에 형성되는 연층은 plume과 천장의 주기적인 충돌에 의해 지배됨을 확인하였다. 또한 plume의 주기적인 충돌은 연층을 두껍게하며, back-flow를 일으킴을 확인하였다. This experiment is to understand a characteristics of smoke layer formation affected periodicity of fire plumes. The ON-OFF jet was used to constitute the oscillating flow, which was formed by a mixture of nitrogen gas with kerosene particles. The instantaneous images was obtained by digital video camera using laser sheet technique. The results were confirmed that the smoke layer in the near fire source comprise vortices which are formed by impingement from the periodicity of fire plume. The periodic impinging of plumes were thickened the smoke layer and produced the back-flow.

First Simultaneous Visualization of SO2 and NO2 Plume Dispersions using Imaging Differential Optical Absorption Spectroscopy

이한림,노영민,권순철,홍현기,한경수 대한화학회 2014 Bulletin of the Korean Chemical Society Vol.35 No.4

Imaging Differential Optical Absorption Spectroscopy (Imaging-DOAS) has been utilized in recent years to provide slant column density (SCD) distributions of several trace gas species in the plume. The present study introduces a new method using Imaging-DOAS data to determine two-dimensional plume structure from the plume emissions of power plant in conditions of negligible aerosol effects on radiative transfer within the plume. We demonstrates for the first time that two-dimensional distributions of sulfur dioxide (SO2) and nitrogen dioxide (NO2) in power plant emissions can be determined simultaneously in terms of SCD distribution. The SO2 SCD values generally decreased with increasing distance from the stack and with distance from the center of the plume. Meanwhile, high NO2 SCD was observed at locations several hundred meters away from the first stack due to the ratio change of NO to NO2 in NOx concentration, attributed to the NO oxidation by O3. The results of this study show the capability of the Imaging-DOAS technique as a tool to estimate plume dimensions in power plant emissions.

Laser- Plume Effects on Radiation Energy Transfer in Materials Processing

Kang, Kae-Myung,Kim, Kwang-Ryul Materials Research Society of Korea 2002 한국재료학회지 Vol.12 No.1

In laser materials processing, localized heating, melting and evaporation caused by focused laser radiation forms a vapor on the material surface. The plume is generally an unstable entity, fluctuating according to its own dynamics. The beam is refracted and absorbed as it traverses the plume, thus modifying its power density on the surface of the condensed phases. This modifies material evaporation and optical properties of the plume. A laser-produced plasma plume simulation is completed using axisymmetric, high-temperature gas dynamic model including the laser radiation power absorption, refraction, and reflection. The physical properties and velocity profiles are verified using the published experimental and numerical results. The simulation results provide the effect of plasma plume fluctuations on the laser power density and quantitative beam radius changes on the material surface. It is proved that beam absorption, reflection and defocusing effects through the plume are essential to obtain appropriate mathematical simulation results. It is also found that absorption of the beam in the plume has much less direct effect on the beam power density at the material surface than defocusing does and helium gas is more efficient in reducing the beam refraction and absorption effect compared to argon gas for common laser materials processing.