scholarly journals Nonhydrostatic Wave Generation at Strained Fronts

2016 ◽  
Vol 73 (7) ◽  
pp. 2837-2850 ◽  
Author(s):  
Callum J. Shakespeare
Keyword(s):  
Numerical Simulations ◽  
Analytical Model ◽  
Strain Field ◽  
Wave Generation ◽  
Vertical Flow ◽  
Simple Analytical Model ◽  
Fully Nonlinear ◽  
Surface Front ◽  
Horizontal Strain ◽  
Hydrostatic Balance

Abstract A simple analytical model is developed to describe wave generation during frontogenesis forced by a horizontal strain field. In contrast to previous models, neither geostrophic nor hydrostatic balance is assumed. The generated waves are trapped in the strain field and form steady bands of enhanced vertical flow on either side of the surface front on scales from 1 to 100 km. The predictions of the analytical model are confirmed by comparison with fully nonlinear numerical simulations.

The spontaneous generation of inertia–gravity waves during frontogenesis forced by large strain: numerical solutions

2015 ◽  
Vol 772 ◽  
pp. 508-534 ◽  
Author(s):  
Callum J. Shakespeare ◽  
J. R. Taylor
Keyword(s):  
Numerical Model ◽  
Analytical Model ◽  
Strain Field ◽  
Numerical Solutions ◽  
Large Strain ◽  
Spontaneous Generation ◽  
Strain Rates ◽  
Fully Nonlinear ◽  
Order Of Magnitude ◽  
Horizontal Strain

A fully nonlinear numerical model is used to investigate spontaneous wave generation during two-dimensional frontogenesis forced by a horizontal strain field. The model uses the idealised configuration of an infinitely long straight front and uniform potential vorticity, with a uniform imposed convergent strain across the front. Shakespeare & Taylor (J. Fluid Mech., vol. 757, 2014, pp. 817–853) formulated a generalised analytical model (ST14) for this system that extends the classical Hoskins & Bretherton (J. Atmos. Sci., vol. 29, 1972, pp. 11–37) model (HB) to large strain rates (${\it\alpha}\sim f$). Here, we use a numerical model to simulate the fully nonlinear problem and compare the results with the predictions of the analytical model for a variety of strain rates. Even for weak strains (${\it\alpha}=0.2f$), the confinement of the secondary circulation and the spontaneous generation of waves, predicted by ST14, are shown to be important corrections to the HB solution. These inviscid predictions are also robust for an equilibrated front where strain-forced frontogenesis is balanced by diffusion. For strong strains the wavefield becomes of leading-order importance to the solution. In this case the frontal circulation is tightly confined, and the vertical velocity is an order of magnitude larger than in the HB model. The addition of a strain field that weakens with time allows the release and propagation of the spontaneously generated waves. We also consider fronts with both large vorticity and strain rate, beyond the validity of the ST14 model.

Convective Losses From Cavity Solar Receivers—Comparisons Between Analytical Predictions and Experimental Results

1983 ◽  
Vol 105 (1) ◽  
pp. 29-33 ◽  
Author(s):  
A. M. Clausing
Keyword(s):  
Experimental Data ◽  
Experimental Evidence ◽  
Analytical Model ◽  
Excellent Agreement ◽  
Experimental Results ◽  
Simple Analytical Model ◽  
Refined Model ◽  
Wall Area

Cavity solar receivers are generally believed to have higher thermal efficiencies than external receivers due to reduced losses. A simple analytical model was presented by the author which indicated that the ability to heat the air inside the cavity often controls the convective loss from cavity receivers. Thus, if the receiver contains a large amount of inactive hot wall area, it can experience a large convective loss. Excellent experimental data from a variety of cavity configurations and orientations have recently become available. These data provided a means of testing and refining the analytical model. In this manuscript, a brief description of the refined model is presented. Emphasis is placed on using available experimental evidence to substantiate the hypothesized mechanisms and assumptions. Detailed comparisons are given between analytical predictions and experimental results. Excellent agreement is obtained, and the important mechanisms are more clearly delineated.

Crypto-steady supersonic pressure exchange: A simple analytical model

2008 ◽  
Vol 85 (4) ◽  
pp. 228-242 ◽  
Author(s):  
Hongfang Zhang ◽  
Charles A. Garris
Keyword(s):  
Analytical Model ◽  
Simple Analytical Model ◽  
Pressure Exchange

The effects of geometric offsets on the dynamic responses of a Scott—Russell amplifying mechanism with flexible hinges

2009 ◽  
Vol 223 (10) ◽  
pp. 2413-2423 ◽  
Author(s):  
C-M Chen ◽  
R-F Fung
Keyword(s):  
Numerical Simulations ◽  
Analytical Model ◽  
Dynamic Responses ◽  
Analytical Models ◽  
Dynamic Equations ◽  
Magnification Factor ◽  
Flexure Hinges ◽  
Magnification Factors ◽  
Straight Line ◽  
Deviation Factor

The dynamic equations of a micro-positioning Scott—Russell (SR) mechanism associated with two flexible hinges and an offset are developed to calculate output responses. Both rigid and flexible hinges are considered to explore the results. The main features in the kinematics of the SR mechanism are its displacement amplification and straight-line motion, which are widely needed in practical industries. The manufacturing inaccuracy of the SR mechanism definitely causes geometric offsets of flexure hinges, and affects displacement amplification and straight-line output motion. Analytical models based on kinematics and Hamilton's principle are derived to explore the variation of linearity ratio, magnification factor, and deviation factor due to various offsets and link lengths. From numerical simulations for the SR mechanism with various offsets of flexible hinges in the conditions of different link lengths, it is found that offsets of flexure hinges obviously affect the amplifying factor and linearity ratio, and appear to dominate the changes of magnification factors. Moreover, an analytical model is also used to predict magnification factors due to various offsets. Finally, some conclusions concerning the effects of offset on the performance of the SR mechanism are drawn.

Shear transfer strength of uncracked interfaces: A simple analytical model

2018 ◽  
Vol 192 ◽  
pp. 366-380 ◽  
Author(s):  
Subhan Ahmad ◽  
Pradeep Bhargava ◽  
Ajay Chourasia
Keyword(s):  
Analytical Model ◽  
Simple Analytical Model ◽  
Shear Transfer

scholarly journals CONTRACTING-OUT OF HOUSEHOLD WASTE COLLECTION SERVICES IN JAPAN

2017 ◽  
Vol 65 (02) ◽  
pp. 443-455
Author(s):  
NORIMICHI MATSUEDA ◽  
JUN’ICHI MIKI
Keyword(s):  
Analytical Model ◽  
Inverse Relationship ◽  
Municipal Waste ◽  
Household Waste ◽  
Private Firms ◽  
Simple Analytical Model ◽  
Waste Collection ◽  
Contracting Out ◽  
Contract Price ◽  
Set Up

We first report three empirical findings from our survey on the contracting-out of municipal waste collection services in Japan: (1) the rate of contracting-out and the contract price are inversely related, (2) this inverse relationship tapers out as the contracting rate becomes sufficiently high, and the contract price even tends to go up as the contracting rate approaches 100% and (3) there is a significant disparity in the contracting rates between the eastern and western parts of Japan. In order to account for these observations, we then set up a simple analytical model and examine its implications. Also, we discuss the issues that a potential hold-up situation could give rise to when the services are completely contracted out to private firms.

scholarly journals Design of thin film solar cells based on a unified simple analytical model

2017 ◽  
Vol 15 (6) ◽  
pp. 599-608 ◽  
Author(s):  
Armando Acevedo-Luna ◽  
Roberto Bernal-Correa ◽  
Jorge Montes-Monsalve ◽  
Arturo Morales-Acevedo
Keyword(s):  
Thin Film ◽  
Solar Cells ◽  
Analytical Model ◽  
Thin Film Solar Cells ◽  
Simple Analytical Model
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