1. Global Warming Problem
Prediction
One of Reasons: CO2 Accumulation in Air

2. Green House Effect Increasing Green House Gases:
Humidity, CO2, Methane, NOx,
Sox etc.
I.R. Absorption
Sun
I.R.
Radiation
Infra Red Absorption into
Green House Gases and
on the Earth surface
Earth
Preserving Heat in the Air
Air
Temperature Rise in the Air
I.R.:Infra Red

3. Imbalance of Carbon Cycle
Measurement at Hawaii ( )
CO2 increase in Air for 30 yrs: 34 ppm
-) Spent Fossile Fuel for 30 yrs: 61 ppm
Missing Sink: -27 ppm
Where?
(Forest, Sea or Others?)

4. Wind Velocity near Sea Surface (Satellite Observation)
Wind Velocity (m/s)

5. CO2 Flux Distribution (Flux=E•DPco2, E=0.03U-3)
(White area: DPco2 data is not available.)

6. Gas Absorption Modeling
Traditional Two-Box Model
- Based on Constant Diffusivity
- Neglect Fluid Dynamic Effect
CO2
Air
Comparison of Surface Layer Thickness
Two-Box Model: 800 m
Measurement: m
Surface Layer
Big Difference!
Sea
Challenge!
Solid line: Two-Box Model
Dashed line: Measurement
Direct Numerical Simulation
Get Gas Exchange Rate at Sea Surf.

7. Turbulent Heat and Mass transfer
Turbulent Free Surface Flows
Establishment of Turbulence Model in Free Surface Flows
Industrial Devices
Fusion Reactor
River, Ocean
Including Free Surface Turbulent Flow
Turbulent Heat and Mass transfer
across Free Surface ?
○　Turbulence Structure
near Free Surface
○　Turbulent Heat and Mass Transfer
across Free Surface
Wind-driven Turbulent Flow
The aim of this study is to investigate the CO2 absorption at the turbulent free-surface deformed by the shear wind, by means of direct numerical solution procedure for a coupled gas-liquid flow: MARS (Multi-interface Advection and Reconstruction Solver).

8. Computational domain and coordinate system
Water
Free-surface
Lx=5h
Lz=10h
Ly=2h h
Bottom wall
Wind
Computational domain and coordinate system

9. Wind
Water
Ly=2h
Lz=10h
Bottom wall
Lx=5h
Bird’s-eye view of Coherent Structure in Wind-driven Turbulent Free Surface Flow
Light green Region: Atmospheric Pressure Contour surface
High Speed Region in Gas-side (Brown),High Speed Region in Water-side (Blue)
Color Section: Streamwise Instantaneous Velocity (-0.01[m/s] Blue<W<2.24[m/s] Red)

10. DNS Result
Need
More Computation
and
Detailed Flow Data

11. Some Common Aspects between Global Warming Problem and Fusion Nuclear Technology from the Perspective of Thermofluid Research*   T. KUNUGI (Kyoto Univ.) and S. SATAKE(Toyama Univ.) * Commentary to J. of Plasma and Fusion Research, Vol.76, No.11, 2000, pp
Scientific interest in the environmental and meteorological fields has been focused on the estimation of the temperature rise on the earth in the near and far future. This problem is strongly related to the imbalance of the amount of carbon on the earth after the industrial revolution; so-called the "Missing Sink" problem. The temperature rise is estimated by the gas transfer flux=(gas transfer rate) x (partial pressure difference of CO2 between air and sea surface). It is very difficult to measure and estimate the gas exchange coefficient resulting from the air-sea interaction because of very high Schmidt number (Sc) turbulent fluid flow with free surface deformation. On the other hand, the utilization of high Prandtl number (Pr) fluid flows with free surface as a coolant in an advanced magnetic fusion reactor and as a chamber protection scheme in an inertial confinement fusion reactor have been considered. Because the diffusivities of high Pr or Sc fluids are very small, when the high temperature or concentration regions appear on the free surface caused by plasma radiation or carbon-dioxide gas absorption respectively, the scalar transport from the free surface to the bulk flow is very slow compared to the fluid motion. In this paper, some common aspects between the heat transfer of high Pr free surface flow in fusion engineering and the mass transfer of high Sc free surface flow in the global warming problem are discussed.