Free convection in the presence of both vertical and horizontal temperature gradients

1977 ◽  
Vol 20 (9) ◽  
pp. 1412 ◽  
Author(s):  
D. Sweet ◽  
E. Jakeman ◽  
D. T. J. Hurle
Keyword(s):  
Free Convection ◽  
Temperature Gradients ◽  
Horizontal Temperature Gradients

A Rule for Forecasting the Eccentricity and Direction of Motion of Tropical Cyclones*

1947 ◽  
Vol 28 (3) ◽  
pp. 121-125 ◽  
Author(s):  
Yale Mintz
Keyword(s):  
Tropical Cyclones ◽  
Temperature Gradients ◽  
Free Air ◽  
The Mean ◽  
The Right ◽  
Horizontal Temperature Gradients

The rule is formulated that in regions with horizontal temperature gradients tropical cyclones are eccentric on the warm air side and move along the mean free air isotherms keeping the warmer air to the right of the direction of motion.

scholarly journals Retrieval of temperature, H<sub>2</sub>O, O<sub>3</sub>, HNO<sub>3</sub>, CH<sub>4</sub>, N<sub>2</sub>O, ClONO<sub>2</sub> and ClO from MIPAS reduced resolution nominal mode limb emission measurements

2009 ◽  
Vol 2 (1) ◽  
pp. 181-236 ◽  
Author(s):  
T. von Clarmann ◽  
M. Höpfner ◽  
S. Kellmann ◽  
A. Linden ◽  
S. Chauhan ◽  
...  
Keyword(s):  
Spectral Resolution ◽  
Time Domain ◽  
Lower Stratosphere ◽  
Temperature Gradients ◽  
Measurement Noise ◽  
High Spectral Resolution ◽  
The Time Domain ◽  
Along Track ◽  
Horizontal Temperature Gradients ◽  
Nominal Mode

Abstract. Retrievals of temperature, H2O, O3, HNO3, CH4, N2O, ClONO2 and ClO from MIPAS reduced spectral resolution nominal mode limb emission measurements outperform retrievals from respective high spectral resolution measurements both in terms of altitude resolution and precision. The estimated precision (including measurement noise and propagation of uncertain parameters randomly varying in the time domain) and altitude resolution are typically 0.5–1.4 K and 3 km for temperature between 10 and 50 km altitude, and 5–6%, 2–4 km for H2O below 30 km altitude, 4–5%, 3–4.5 km for O3 between 15 and 40 km altitude, 3–8%, 3–5 km for HNO3 between 10 and 35 km altitude, 5–8%, 3 km for CH4 between 15 and 35 km altitude, 5–10%, 3 km for N2O between 15 and 35 km altitude, 8–14%, 2.5–9 km for ClONO2 below 40 km, and larger than 35%, 5–6 km for ClO in the lower stratosphere. As for the high spectral resolution measurements, the reduced spectral resolution nominal mode horizontal sampling (410 km) is coarser than the horizontal smoothing (often below 400 km), depending on species, altitude and number of tangent altitudes actually used for the retrieval. Thus, aliasing might be an issue even in the along-track domain. In order to prevent failure of convergence, it was found to be essential to consider horizontal temperature gradients during the retrieval.

Computational Study of the Heat Transfer of the Buoyancy-Driven Rotating Cavity With Axial Throughflow of Cooling Air

2009 ◽  
Author(s):  
Zain Dweik ◽  
Roger Briley ◽  
Timothy Swafford ◽  
Barry Hunt
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Free Convection ◽  
Flat Plate ◽  
Computational Study ◽  
Operating Conditions ◽  
Temperature Gradients ◽  
Wide Range ◽  
Complete Set ◽  
The Impact

Buoyancy driven flows that occur in the inter-disk space of an axial compressor spool play a major role in projecting gas turbine engine life and performance. The Rayleigh-Benard-like flow structure developed under the influence of centrifugal buoyancy creates sharp temperature gradients at the rotating walls of the compressor hardware. These sharp temperature gradients greatly influence the running stresses inside the machine and therefore affecting its life. The objective of this work is to generate a complete set of computationally-derived Nusselt number correlations that will be used in conducting the conjugate heat transfer analyses. The impact of engine power condition (Idle, Highpower, and Shutdown) on the heat transfer of these rotating cavities is studied under the wide range of operating conditions encountered by realistic turbomachines. A computational analysis is performed using commercially available computational tools for grid generation (ICEM-CFD) and turbulent-flow simulation (CFX). A total of fifty steady CFD cases for two different cavity configurations were analyzed. The CFD computed results of these cases were used to generate a complete set of Nusselt number correlations for different cavity geometry (gap ratios), flow regimes (forced and free convection dominated regimes), and operating conditions (Rossby Number Ro, Rotational Rayleigh Number RaΩ, and axial Reynolds Number Rez). The CFD computed heat-transfer results revealed that, despite the complicated flow patterns inside these cavities, and despite the large variation in their geometry, the simple Nusselt number correlations for free convection from a vertical flat plate with constant temperature can be used to predict the global Nusselt number values for the buoyancy-dominated regime of all such cavities. Furthermore, the Nusselt number correlations for the laminar and turbulent forced convection over a flat plate can be used to predict the global Nusselt number values for the central-jet dominated regime.

scholarly journals Well-balanced finite volume multi-resolution schemes for solving the Ripa models

2021 ◽  
Vol 13 (3) ◽  
pp. 168781402110034
Author(s):  
Asad Rehman ◽  
Ishtiaq Ali ◽  
Saqib Zia ◽  
Shamsul Qamar
Keyword(s):  
Steady State ◽  
Finite Volume ◽  
Numerical Test ◽  
Temperature Gradients ◽  
Water Model ◽  
Test Problems ◽  
Numerical Schemes ◽  
Weno Schemes ◽  
Horizontal Temperature Gradients ◽  
Fifth Order

In this article, fifth order well-balanced finite volume multi-resolution weighted essentially non-oscillatory (FV MR-WENO) schemes are constructed for solving one-dimensional and two-dimensional Ripa models. The Ripa system generalizes the shallow water model by incorporating horizontal temperature gradients. The presence of temperature gradients and source terms in the Ripa models introduce difficulties in developing high order accurate numerical schemes which can preserve exactly the steady-state conditions. The proposed numerical methods are capable to exactly preserve the steady-state solutions and maintain non-oscillatory property near the shock transitions. Moreover, in the procedure of derivation of the FV MR-WENO schemes unequal central spatial stencils are used and linear weights can be chosen any positive numbers with only restriction that their total sum is one. Various numerical test problems are considered to check the validity and accuracy of the derived numerical schemes. Further, the results obtained from considered numerical schemes are compared with those of a high resolution central upwind scheme and available exact solutions of the Ripa model.

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