Marine Turbulent Boundary Layer Fluxes of Water Vapor, Sensible Heat and Momentum During Gate

1978 ◽  
pp. 21-33 ◽  
Author(s):  
B. R. Bean ◽  
R. F. Reinking
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Turbulent Boundary Layer ◽  
Sensible Heat

On the Challenges of Tomography Retrievals of a 2D Water Vapor Field Using Ground-Based Microwave Radiometers: An Observation System Simulation Experiment

2015 ◽  
Vol 32 (1) ◽  
pp. 116-130 ◽  
Author(s):  
Véronique Meunier ◽  
David D. Turner ◽  
Pavlos Kollias
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Turbulent Boundary Layer ◽  
Covariance Matrix ◽  
A Priori ◽  
Simulated Data ◽  
Optimal Estimation ◽  
Estimation Algorithm ◽  
Observation System ◽  
Microwave Radiometers

AbstractTwo-dimensional water vapor fields were retrieved by simulated measurements from multiple ground-based microwave radiometers using a tomographic approach. The goal of this paper was to investigate how the various aspects of the instrument setup (number and spacing of elevation angles and of instruments, number of frequencies, etc.) affected the quality of the retrieved field. This was done for two simulated atmospheric water vapor fields: 1) an exaggerated turbulent boundary layer and 2) a simplified water vapor front. An optimal estimation algorithm was used to obtain the tomographic field from the microwave radiometers and to evaluate the fidelity and information content of this retrieved field.While the retrieval of the simplified front was reasonably successful, the retrieval could not reproduce the details of the turbulent boundary layer field even using up to nine instruments and 25 elevation angles. In addition, the vertical profile of the variability of the water vapor field could not be captured. An additional set of tests was performed using simulated data from a Raman lidar. Even with the detailed lidar measurements, the retrieval did not succeed except when the lidar data were used to define the a priori covariance matrix. This suggests that the main limitation to obtaining fine structures in a retrieved field using tomographic retrievals is the definition of the a priori covariance matrix.

Effects of Injection on Condensation on a Film-Cooled Surface

1987 ◽  
Author(s):  
William Phil Webster ◽  
Savash Yavuzkurt
Keyword(s):  
Boundary Layer ◽  
Water Vapor ◽  
Turbulent Boundary Layer ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Free Stream ◽  
Stream Water ◽  
Turbine Blades ◽  
Stream Velocity ◽  
Test Surface

Gas turbine blades have previously been shown to corrode due to condensation of sulfide vapor on a cooled blade surface. In the present investigation, water vapor was condensed on a film cooled surface, simulating the condensation of sulfide vapor on a turbine blade. The injection section consisted of one row of holes (inner diameter of 1.0 cm) inclined 30 degrees with the surface and inline with the main turbulent boundary layer flow. Experiments were carried out in a subsonic, zero pressure gradient, turbulent boundary layer with free stream velocities of 10.5, 15.75, and 21.0 m/sec. A cooling fluid (water at near 0°C) was circulated through the plate, cooling the test surface and causing free stream water vapor to condense. Measurements were made at three Reynolds numbers (based on hole diameter and free stream velocity): 7,000, 10,500, and 14,000; and at three blowing ratios: 0.4, 0.8, 1.2. The results show the existence of a “dryout” region downstream of each cooling hole. This region was dry while regions between the jets had water on the surface. This dryout region was triangularly shaped, with the apex as much as 30 jet diameters from the downstream edge of the jet. For each Reynolds number the lowest blowing ratio (M = 0.4) had the largest dryout region. These results indicate that injection can be used to prevent condensation of corrosive vapors on a film-cooled gas turbine blade.

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