scholarly journals The characterization of turbulent heat and moisture transport during a gust-front event over the Indian peninsula

2021 ◽  
Author(s):  
Subharthi Chowdhuri ◽  
Kiran Todekar ◽  
Thara V Prabha
Keyword(s):  
Moisture Transport ◽  
Turbulent Heat ◽  
Indian Peninsula ◽  
Heat And Moisture Transport ◽  
Heat And Moisture ◽  
Gust Front

The characterization of turbulent heat and moisture transport during a gust-front event over the Indian peninsula

2021 ◽  
Author(s):  
Subharthi Chowdhuri ◽  
Kiran Todekar ◽  
Thara V Prabha
Keyword(s):  
Time Scales ◽  
Power Law ◽  
Moisture Transport ◽  
Cold Pool ◽  
Turbulent Heat ◽  
Power Law Distribution ◽  
Indian Peninsula ◽  
Heat And Moisture Transport ◽  
Heat And Moisture ◽  
Gust Front

Abstract The ramifications of gust-front on atmospheric surface layer (ASL) turbulence is a vexing issue, with nearly no information available over the Indian region where such events are not uncommon. Over the Indian peninsula, Chowdhuri et al. (Environ. Fluid Mech. 21(1):263–281, 2021) have shown that, the cold pool associated with the gust-front creates two distinct regimes in ASL turbulence, where the temperature fluctuations display contrasting behavior. To evaluate the corresponding impacts on the moisture fluctuations and turbulent heat and moisture transport, we extend our analysis by using the same field-experimental dataset of Chowdhuri et al. (2021). We discover that, the topology of the turbulent structures which govern the temperature and moisture fluctuations clearly exhibit a regime-wise distinction. In the first regime, the structures in temperature and moisture fluctuations are significantly inclined in the vertical, while demonstrating a self-similarity in their time scales by being related through a power-law distribution. However, in the second regime, the vertical inclination disappears for the temperature structures with hardly any change observed for the moisture. Moreover, the power-law exponents of the turbulent temperature time scales remain sensitive to the regimes, although no such effect is visible in the power-law character of the moisture time scales. Additionally, the dissimilarity in the heat and moisture transport is investigated through a novel polar-quadrant based approach that separates the phases and amplitudes of the flux-transporting motions.

scholarly journals Heat and Moisture Transport in Multi-Layer Walls: Interaction and Heat Loss at Varying Outdoor Temperatures / Siltuma Un Mitruma Pārnese Caur Daudzslāņainām Būvkonstrukcijām: Āra Temperatūras Izmaiņu Ietekme Uz Siltuma Zudumiem Iekštelpā

2012 ◽  
Vol 49 (6-I) ◽  
pp. 32-43 ◽  
Author(s):  
A. Ozolinsh ◽  
A. Jakovich
Keyword(s):  
Mathematical Model ◽  
Energy Efficiency ◽  
Moisture Transport ◽  
Heat Losses ◽  
Condensate Formation ◽  
Heat And Moisture Transport ◽  
U Value ◽  
Technical Solutions ◽  
Heat And Moisture ◽  
Humidity Profiles

Abstract The heat and moisture transport in multi-layer walls is analysed for five building units. Using the developed program, a typical of Latvian conditions temperature and relative humidity profiles in multi-layered constructions has been obtained and the indoor heat losses estimated. Consideration is also given to the risk of condensate formation and to the influence of moisture on the U-value. The created mathematical model allows forecasting the energy efficiency and sustainability of different technical solutions as refer to the heat and moisture transport in buildings.

Heat and Moisture Transport Through the Micro-Climate Air Annulus of the Clothing-Skin System Under Periodic Motion

2005 ◽  
Author(s):  
N. Ghaddar ◽  
K. Ghali ◽  
E. Jaroudi
Keyword(s):  
Heat Loss ◽  
Latent Heat ◽  
Moisture Transport ◽  
Contact Region ◽  
Heat Losses ◽  
Sensible Heat ◽  
Skin Contact ◽  
Cylinder Model ◽  
Heat And Moisture Transport ◽  
Heat And Moisture

A dynamic thermal model is developed using the 2D cylinder model of Ghaddar et al [1] of ventilated fabric-skin system where a microclimate air annulus separates an outer cylindrical fabric boundary and an inner human body solid boundary for closed and open apertures. The cylinder model solves for the radial, and angular flow rates in the microclimate air annulus domain where the inner cylinder is oscillating within an outer fixed cylinder of porous fabric boundary. The 2-D cylinder model is further developed in the radial and angular directions to incorporate the heat and moisture transport from the inner cylinder when the fabric touches the skin boundary at repetitive finite intervals during the motion cycle. The touch model is based on a lumped fabric transient approach based on the fabric dry and evaporative resistances at the localized touch regions at the top and bottom of points of the cylinder. The film coefficients at the inner cylinder are needed for the model simulation. Experiments are conducted in an environmental chamber under controlled conditions to measure the mass transfer coefficient at the skin to the air annulus separating the wet skin and the fabric in the cylindrical geometry. In addition, experiments have also been conducted at ventilation frequencies of 30, 40, and 60 rpm to measure the sensible heat loss from the inner cylinder to validate the predictions of sensible and latent heat losses of the 2-D ventilation model for the two cases when fabric is in contact with the skin surface and when no contact is present for close aperture. The model prediction of time-averaged steady-periodic sensible heat loss agreed well with the experimentally measured values. A parametric study is performed to predict sensible and latent heat losses from the system by ventilation at different frequencies, fabric skin contact times during the motion cycle measured by a dimensionless amplitude parameter (ζ = amplitude/mean annular spacing). The rate of heat loss increases with increased ventilation frequency at fixed ζ. The latent heat loss in the contact region increases by almost 40% due to increase in fabric temperature during contact. The sensible heat loss decreases between 3% at f = 60 rpm, and 5% at f = 25 rpm in the contact region due to higher air temperature and lack of heat loss by radiation during the contact between fabric and skin.

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