• 제목/요약/키워드: velocity decomposition

검색결과 201건 처리시간 0.028초

Enhanced data-driven simulation of non-stationary winds using DPOD based coherence matrix decomposition

  • Liyuan Cao;Jiahao Lu;Chunxiang Li
    • Wind and Structures
    • /
    • 제39권2호
    • /
    • pp.125-140
    • /
    • 2024
  • The simulation of non-stationary wind velocity is particularly crucial for the wind resistant design of slender structures. Recently, some data-driven simulation methods have received much attention due to their straightforwardness. However, as the number of simulation points increases, it will face efficiency issues. Under such a background, in this paper, a time-varying coherence matrix decomposition method based on Diagonal Proper Orthogonal Decomposition (DPOD) interpolation is proposed for the data-driven simulation of non-stationary wind velocity based on S-transform (ST). Its core idea is to use coherence matrix decomposition instead of the decomposition of the measured time-frequency power spectrum matrix based on ST. The decomposition result of the time-varying coherence matrix is relatively smooth, so DPOD interpolation can be introduced to accelerate its decomposition, and the DPOD interpolation technology is extended to the simulation based on measured wind velocity. The numerical experiment has shown that the reconstruction results of coherence matrix interpolation are consistent with the target values, and the interpolation calculation efficiency is higher than that of the coherence matrix time-frequency interpolation method and the coherence matrix POD interpolation method. Compared to existing data-driven simulation methods, it addresses the efficiency issue in simulations where the number of Cholesky decompositions increases with the increase of simulation points, significantly enhancing the efficiency of simulating multivariate non-stationary wind velocities. Meanwhile, the simulation data preserved the time-frequency characteristics of the measured wind velocity well.

속도분리를 이용한 여유자유도 로봇의 최적 경로계획 (An Optimal Trajectory Planning for Redundant Robot Manipulators Based on Velocity Decomposition)

  • 이지홍;원경태
    • 제어로봇시스템학회논문지
    • /
    • 제5권7호
    • /
    • pp.836-840
    • /
    • 1999
  • Linear motion and angular motion in task space are handled separately in joint velocity planning for redundant robot manipulators. In solving inverse kinematic equations with given joint velocity limits, we consider the order of priority for linear motion and angular motion. The proposed method will be useful in such applications where only linear motions are important than angular motions or vice versa.

  • PDF

Ammonia decomposition over titanium carbides

  • Choi, Jeong-Gil
    • 한국결정성장학회지
    • /
    • 제22권6호
    • /
    • pp.269-273
    • /
    • 2012
  • Ammonia decomposition over titanium carbides were investigated using eight different samples which have been synthesized by TPR (temperature-programmed reduction) method of titanium oxide ($TiO_2$) with pure $CH_4$. The resulting materials which were synthesized using wo different heating rates and space velocity exhibited the different surface areas. These results indicated that the structural properties of these materials have been related to heating rates and space velocity employed. The titanium carbides prepared in this study proved to be active for ammonia decomposition, and the activity changed with the particle size/surface area. These showed the relationship between ammonia decomposition activity and the different active species. Compared to molybdenum carbide, the titanium carbides were one order of magnitude less active, suggesting the correlation between the activity difference and the degree of electron transfer between metals and carbon in metal carbides.

탄소성 변형구배텐서의 가산분해와 곱분해에 대한 새로운 역학적 이해 (A New Interpretation on the Additive and Multiplicative Decompositions of Elastic-Plasmic Deformation Gradient Tensor)

  • 남용윤;신종계
    • 대한조선학회논문집
    • /
    • 제33권3호
    • /
    • pp.94-102
    • /
    • 1996
  • 유한변형문제에서 변형구배텐서를 탄소성 성분으로 분해하기 위한 가산분해와 곱분해방법에 대해서 설명하고, 이 두 방법에서 파생되는 역학량들의 의미와 그 차이점을 보였다. 변형구배에 대한 기존의 곱분해와 가산분해로 얻어지는 변형속도구배는 가산적으로 표현되지 않으며, 소성변형속도구배는 탄성변형의 영향을 받고 있다. 본 연구에서는 공축소성 가정을 도입하고, 수정된 곱분해를 통하여 소성변형속도구배가 탄성변형에 영향을 받지 않는 가산적인 변형속도 구배를 얻었다.

  • PDF

카본블랙 촉매를 이용한 유동층 반응기에서 메탄의 직접 열 분해에 의한 수소생산 연구 (Hydrogen production by catalytic decomposition of methane over carbon black catalyst in a fluidized bed)

  • 정재욱;남우석;윤기준;이동현;한귀영
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 한국신재생에너지학회 2005년도 춘계학술대회
    • /
    • pp.284-287
    • /
    • 2005
  • A fluidized bed reactor made of quartz with 0.055 m I.D. and 1.0 m in height was employed for the thermocatalytic decomposition of methane to produce $CO_2 - free$ hydrogen. The fluidized bed was proposed for the continuous withdraw of product carbons from the reactor. The methane decomposition rate with the carbon black N330 catalyst was quickly reached a quasi-steady state rate and remained for several hour. The methane decomposition reaction was carried out at the temperature range of $850-925^{\circ}C$, methane gas velocity of $1.0U_{mf}\;3.0U_{mf}$ and the operating pressure of 1.0 atm. Effect of operating parameters such as reaction temperature, gas velocity on the reaction rates was investigated. The produced carbon by the methane decomposition was deposited on the surfaces of carbon catalysts and the morphology was observed by SEM image.

  • PDF

카본블랙 촉매를 이용한 유동층 반응기에서 메탄과 프로판 혼합물의 촉매 분해에 의한 수소생산 연구 (Hydrogen production by catalytic decomposition of methane and propane mixture over carbon black catalyst in a fluidized bed)

  • 이승철;윤용희;한귀영
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 한국신재생에너지학회 2007년도 춘계학술대회
    • /
    • pp.57-60
    • /
    • 2007
  • A fluidized bed reactor made of quartz with 0.055 m I.D. and 1.0 m in height was employed for the thermocatalytic decomposition of methane to produce $CO_{2}$ - free hydrogen. The fluidized bed was proposed for the continuous withdraw of product carbons from the reactor. The methane decomposition rate with the carbon black N330 catalyst was quickly reached a quasi-steady state rate and remained for several hour. The methane and propane mixture decomposition reaction was carried out at the temperature range of 850 - 900 $^{\circ}C$, methane and propane mixture gas velocity of 1.0 $U_{mf}$ ${\sim}$ 3.0 $U_{mf}$ and the operating pressure of 1.0 atm. Effect of operating parameters such as reaction temperature, gas velocity on the reaction rates was investigated. The produced carbon by the methane decomposition was deposited on the surfaces of carbon catalysts and the morphology was observed by SEM image.

  • PDF

카본블랙 촉매를 이용한 유동층 반응기에서 메탄과 프로판 혼합물의 촉매 분해에 의한 수소생산 연구 (Hydrogen production by catalytic decomposition of methane and propane mixture over carbon black catalyst in a fluidized bed)

  • 이승철;윤용희;한귀영
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 한국신재생에너지학회 2007년도 추계학술대회 논문집
    • /
    • pp.97-100
    • /
    • 2007
  • A fluidized bed reactor made of quartz with 0.055 m I.D. and 1.0 m in height was employed for the thermocatalytic decomposition of methane to produce $CO_2$ - free hydrogen . The fluidized bed was proposed for the continuous withdraw of product carbons from the reactor. The methane decomposition rate with the carbon black N330 catalyst was quickly reached a quasi-steady state rate and remained for several hour. The methane and propane mixture decomposition reaction was carried out at the temperature range of 850 - 900 $^{\circ}C$, methane and propane mixture gas velocity of 1.0 $U_{mf}$ ${\sim}$ 3.0 $U_{mf}$ and the operating pressure of 1.0 atm. Effect of operating parameters such as reaction temperature, gas velocity on the reaction rates was investigated. The produced carbon by the methane decomposition was deposited on the surfaces of carbon catalysts and the morphology was observed by TEM image.

  • PDF

유동층 반응기에서 카본블랙 촉매를 이용한 프로판의 촉매 분해에 의한 수소생산 연구 (Hydrogen production by catalytic decomposition of propane over carbon black catalyst in a fluidized bed)

  • 정재욱;남우석;윤기준;이동현;한귀영
    • 한국신재생에너지학회:학술대회논문집
    • /
    • 한국신재생에너지학회 2006년도 춘계학술대회
    • /
    • pp.85-88
    • /
    • 2006
  • A fluidized bed reactor made of quartz with 0.055m I.D. and 1.0m in height was employed for the thermocatalytic decomposition of propane to produce $CO_2$-free hydrogen. The fluidized bed was proposed for the continuous withdraw of product carbons from the reactor. The propane decomposition rate used carbon black N33O as a catalyst. The propane decomposition reaction was carried out at the temperature range of $600{\sim}800^{\circ}C$, paropane gas velocity of $1.0 U_{mf}\;3.0U_{mf}$ and the operating pressure of 1.0 atm. Effect of operating parameters such as reaction temperature, gas velocity on the reaction rates was investigated. The carbon which was by-product of methane decomposition reaction was deposited on the catalyst surface that was observed by SEM. Resulting production in our experiment were not only hydrogen but also several by products such as methane, ethylene, ethane, and propylene.

  • PDF

APPLICATION OF DOUBLE DECOMPOSITION TO PULSATILE FLOW

  • Mamaloukas, C.;Haldar, K.;Mazumdar, H.P.
    • Journal of applied mathematics & informatics
    • /
    • 제10권1_2호
    • /
    • pp.193-207
    • /
    • 2002
  • The present investigation deals with the pulsatile flow of incompressible viscous fluid through a circular rigid tube provided with constriction. The method applied here is the Decomposition Method, which has been developed by George Adomian [3]. The advantages of this method are the avoidance of simplifications and restrictions, which change the non-linear problem to mathematically tractable one, whose solution is not consistent with physical solution. Theoretically results, such as, wall shear stress and axial velocity component, have been obtained and the graphical solutions of these theoretical results have been shown in the figures.

TWO-DIMENSIONAL SIMULATION OF HYDROGEN IODIDE DECOMPOSITION REACTION USING FLUENT CODE FOR HYDROGEN PRODUCTION USING NUCLEAR TECHNOLOGY

  • CHOI, JUNG-SIK;SHIN, YOUNG-JOON;LEE, KI-YOUNG;CHOI, JAE-HYUK
    • Nuclear Engineering and Technology
    • /
    • 제47권4호
    • /
    • pp.424-433
    • /
    • 2015
  • The operating characteristics of hydrogen iodide (HI) decomposition for hydrogen production were investigated using the commercial computational fluid dynamics code, and various factors, such as hydrogen production, heat of reaction, and temperature distribution, were studied to compare device performance with that expected for device development. Hydrogen production increased with an increase of the surface-to-volume (STV) ratio. With an increase of hydrogen production, the reaction heat increased. The internal pressure and velocity of the HI decomposer were estimated through pressure drop and reducing velocity from the preheating zone. The mass of $H_2O$ was independent of the STV ratio, whereas that of HI decreased with increasing STV ratio.