第111回計算科学コロキウムを、10月14日（金）に開催します。
多数のご来聴をお願い致します。

日時：2016年10月14日（金） 10:30-12:00
場所：筑波大学　計算科学研究センター　　会議室C
題目：Instanton Theory and the Role of Atom-Tunneling in Astrochemical Reactions
講師：Prof. Dr. Johannes Kästner
University of Stuttgart Inst. for Theoretical Chemistry

要旨:
Simulations of reaction rates including quantum tunneling of atoms complement measurements provide input for astrochemical models. An appropriate rate theory must be accurate enough to provide reliable predictions, but efficient enough to allow for computationally intensive electronic structure calculations at large enough structural models. Instanton theory, based on Feynman path integrals, matches these requirements [1]. It provides the dominant tunneling path at a given temperature or energy.
We have used instanton theory to calculate rate constants for a number of reactions of astrochemical interest both in the gas phase and on surfaces. Examples are:
H₂ + OH ⟶ H₂O + H [2]
CH₃OH + H˙⟶˙CH₂OH + H₂ [3]
HNCO + H ⟶ NH₂CO [4]
Models of surface reactions need to include the interplay between reactions and diffusion.

Figure 1: Tunneling path (instanton path) of the reaction HNCO + H ⟶ NH2CO on a surface of amorphous solid water [4]. The path is colored from the reactant side (red) to the product side (blue).

References
[1] J. Meisner and J. Kästner, 2016, Angew. Chem. Int. Ed. 55, 5400
[2] J. Meisner and J. Kästner, 2016, J. Chem. Phys. 144, 174303
[3] T.P.M. Goumans, J. Kästner, 2011, J. Phys. Chem. A 115, 10767
[4] L. Song and J. Kästner, 2016, Phys. Chem. Chem. Phys. accepted

世話人：相川 祐理

第110回計算科学コロキウムを、9月19日（月・祝）に開催します。
多数のご来聴をお待ちしております。

日時：2016年9月19日（月・祝）9:30-
場所：筑波大学　計算科学研究センター　国際ワークショップ室
題目：Wind Energy Modelling from a Wind Farm to a Wind Blade Scale / Recent Innovations in Wind Engineering in Norway and Potential for Collaborations
講師：Dr. Adil Rasheed
Applied Mathematics Department, SINTEF ICT

要旨:
The presentation comprises of two parts. The first part gives an overview of the wind energy related research activities in Norway. Research themes of two relevant projects; NOWITECH (Norwegian Research Centre for Offshore Wind Technology) and NORCOWE (Norwegian Centre for Offshore Wind Energy) is presented. The second part of the presentation starts with a demonstration of Isogeometric Analysis, a new numerical discretization technique to model flow and fluid-structure interactions in two dimensions. This is followed by a critical evaluation of the assumptions made in the use of simplified methodologies like Blade Element Method (BEM) and Strip Theory (ST) for modelling aerodynamic behaviour of wind turbines. A comparison of the computational cost and accuracy associated with Multiple Reference Frame (MRF) and Sliding Mesh Interface strategies (SMI) is presented next in the context of flow around a rotating turbine. MRF because of its computational efficiency is then chosen to conduct several sensitivity analysis. A detailed explanation of the torque output from a turbine as a function of different tip speed ratio and inlet turbulence intensity is given. Moving to larger scales, the focus shifts to wake-terrain interaction in a windfarm setting followed by ocean-atmospheric interactions. The benefits of bi-directional coupling between stochastic wave model and deterministic atmospheric model is demonstrated through a comparison of predicted wave height, and vertical wind and temperature profiles with sea buoy and radiosonde measurements. Towards the end, research topics and potential of new collaborations are discussed.

世話人：日下 博幸

第109回計算科学コロキウムを、9月16日（金）に開催します。
多数のご来聴をお待ちしております。

日時：2016年9月16日（金）9:30-
場所：筑波大学　総合研究棟A棟110（公開講義室）[MAP]
題目：A survey of diurnal and terrain-forced mountain wind systems
講師：Prof. C. David Whiteman
Atmospheric Sciences Department, University of Utah

要旨:
This presentation will provide a broad overview of meteorological research in Europe and North America on wind systems in mountainous areas. The presentation will be broken into two parts – the first will focus on diurnal wind systems in valleys and basins that reverse twice per day including slope, valley, cross-valley and mountain-plain flows. The second will cover the modification by topography of larger-scale flows approaching a mountainous area. These topics will include flows over and around mountain massifs and flow channeling through valleys and passes.

世話人：日下 博幸