The Vertical Transport of Air Pollutants by Convective Clouds Part Ⅱ：Transport of Soluble Gases and Sensitivity Tests

A two-dimensional, non-reactive convective cloud transport model is used to simulate in detail the vertical transport and wet scavenging of soluble pollutant gases by a deep thunderstorm systems Simulations show that for gases with not very high solubility, a deep and intense thunderstorm can still rapidly and efficiently transport them from boundary layer(PBL) up to mid and upper troposphere. resulting in a local significant increase of concentration in the upper layer and a reduction in PBL. Dissolution effects decrease both the incloud gas concentration and the upward net fluxes. The higher the solubility is, the more remarkable the decrease is. However, for very low soluble gases (H<102 Matm-1), the influences are very slight. In addition, the effects of irreversible dissolution and aqueous reactions in drops on the vertical transport of gaseous pollutants are estimated in extreme.

The Vertical Transport of Air Pollutants by Convective Clouds．Part Ⅲ：Transport Features of Different Cloud Systems

The vertical transport features of gaseous pollutants, with a negative exponent profile of concentration, by different types of convective cloud systems are numerically investigated by using a two-dimensional, reactlonless convective cloud transport model. The results show that an isolated, weak storm is able to pump pollutant gas out PBL and transport it to the mid-troposphere, whereas a deep. intense thunderstorm can very efficiently transport air pollutants up to the mid and upper troposphere and laterally spread with anvil, forming an extensive concentration surge layer at aliitnde of ten odd kilometers altitude. Each type of convective transport results in concentration reduction in PHL. In a wind shear environment the transport efficiency of deep thunderstorm significantly increases and the pollutants enter into clouds on the downshear side at low level and spread downwind in anvil layer. On the other hand, for a cumulus cloud with plenty of liquid water. the gas dissolution effect is increased, and the irreversible aqueous reactions, in extreme, may significantly weaken the vertical transports of pollutant gases even with solubility coefficients no more than 103 M atm-1.

Impact of Convective Momentum Transport by Deep Convection on Simulation of Tropical Intraseasonal Oscillation

This paper focuses on the impacts of convective momentum transport(CMT) on simulations of the tropical intraseasonal oscillation(TIO) in SAMIL. Two sets of experiments are performed, which give different reality of the Madden-Julian Oscillation(MJO). The Tiedtke cumulus parameterization scheme is used for all experiments. It is found that simulations of the TIO can be influenced by CMT, and the impacts on the simulated TIO depend on the model capability in simulating the MJO. CMT tends to have large influences to the model that can simulate the eastward propagation of the MJO. CMT can further influence the long-term mean of zonal wind and its vertical shear. Zonal wind suffers from easterlies biases at low level and westerlies biases at upper level when CMT is introduced. Such easterlies biases at low level reduce the reality of the simulated tropical intraseasonal oscillation. When CMT is introduced in the model, MJO signals disappear but the model's mean state improves. Therefore, a more appropriate way is needed to introduce CMT to the model to balance the simulated mean state and TIO signals.

Mixed convective heat and mass transfer analysis for peristaltic transport in an asymmetric channel with Soret and Dufour effects

The present investigation addresses the simultaneous effects of heat and mass transfer in the mixed convection peristaltic flow of viscous fluid in an asymmetric channel. The channel walls exhibit the convective boundary conditions. In addition, the effects due to Soret and Dufour are taken into consideration. Resulting problems are solved for the series solutions. Numerical values of heat and mass transfer rates are displayed and studied. Results indicate that the concentration and temperature of the fluid increase whereas the mass transfer rate at the wall decreases with increase of the mass transfer Biot number. Furthermore, it is observed that the temperature decreases with the increase of the heat transfer Biot number.

Hydrodynamic Instabilities Driven by Acid-base Neutralization Reaction in Immiscible System

The hydrodynamic instabilities driven by an acid-base neutralization reaction, in contact along a plane interface, placed in a Hele-Shaw cell under the gravitational field are reported. The system consists of the heavier aqueous tetramethyle-ammonium hydroxide below the lighter layer of organic phase with propionic acid as reacting specie. The effect of chemical composition on hydrodynamic instabilities during interfacial mass transfer accompanied by a neutralization reaction is investigated. Depending on the initial concentration of the reacting species, Marangoni convection in the form of roll ceils or trains of waves is observed. Mach- Zehnder interferometer is used to measure the change in base concentration at the time of instability formation. The results show that the instabilities resulted from the convection flow are more efficient to the mechanism of mass transfer and can drastically alter pattern formation in the system.

Base Pressure Plays an Important Role for Production of Plasma Blob in Argon Plasma

Magnetic confinement of fusion plasma has a wide range of issues to be addressed. Convective transport of plasma in the scrape-off layer of magnetic confinement devices is an interesting research topic for scientists and engineers. The interest in scrape-off layer convective transport has grown in last two decades because of its effect on plasma interaction with the first wall and divertor. By increasing the particle flux into the far scrape-off layer, blobs negatively affect limiters, radio frequency antennas and the first wall. Increased convective heat transport influences core plasma confinement, at least in L-mode plasmas. Here we have reported blob formation in the absent of external magnetic field. It is observed that at low pressure -0.01 rob, transport seems to be dominated by diffusive process. At pressure 〉 1 mb, we observe convective transport in high speed imaging experiments. The role of background neutrals outside plasma boundary has the befitting answer for this phenomenon. Plasma temperature is the other key player. Another interesting observation is that at diffusive transport regime plasma life time is of the order of voltage pulse duration fed to plasma source, where as at convective transport regime plasma life time is increased appreciably.

Comparison of ELM-Filament Mitigation Between Supersonic Molecular Beam Injection and Pellet Injection on HL-2A

On HL-2A,two different injections（supersonic molecular beam injection（SMBI）and pellet injection（PI）） are used to mitigate edge localized mode（ELM）-filament convective transport.The changes of their characteristics are studied in this paper.A high spatiotemporal resolution probe shows there are many similar phenomena,and the filament density amplitude and radial velocity are both suppressed.Our statistical results indicate that：the velocity suppression comes from the decrease of filament density and temperature;the transient particle and heat fluxes drop strongly;and long-range correlation along a magnetic flux surface also decreases,when the electron-ion collisionality increases significantly,which may have a role on the filament parallel current during ELM mitigation.