scholarly journals Interaction of an Asymmetric Double Vortex and Trochoidal Motion of a Tropical Cyclone with the Concentric Eyewall Structure

2006 ◽  
Vol 63 (3) ◽  
pp. 1069-1081 ◽  
Author(s):  
Masahito Oda ◽  
Mikio Nakanishi ◽  
Gen’ichi Naito
Keyword(s):  
Tropical Cyclone ◽  
Numerical Experiment ◽  
Tropical Cyclones ◽  
Rotation Period ◽  
Echo Intensity ◽  
Dynamics Model ◽  
The Third ◽  
Radar Echo ◽  
The Relationship ◽  
Typhoon Herb

Abstract Radar echo images demonstrate that mature tropical cyclones frequently have a concentric eyewall structure, which consists of the inner eyewall, echo-free moat, and outer eyewall regions. Near the inner and outer eyewalls, well-defined wind maxima are generally observed. This indicates that two large vertical vorticity regions exist just inside radii of the two wind maxima near the inner and outer eyewalls. Therefore, the concentric eyewall structure can be considered to be a double vortex composed of the inner vortex and the outer vortex ring. In this study, the contour dynamics model is used on the f plane to analyze the characteristics of flows with either a symmetric double vortex or an asymmetric one, and examined the relationship between the movement of the inner vortex in an asymmetric double vortex and a trochoidal motion of a tropical cyclone with an asymmetric concentric eyewall structure. Results show that, depending on the degree of an interaction of a double vortex, the evolution of the inner vortex is classified into three patterns: the first is that the center of the inner vortex is stationary, which is seen only for the symmetric double vortex; the second is that the track of the center of the inner vortex draws a circle; and the third is that it draws a spiral. A numerical experiment based on an observed flow around Typhoon Herb was also performed. The time evolution of the double vortex is very similar to that of radar echo intensity of Typhoon Herb. Also the rotation period and amplitude of the inner vortex in the numerical experiment were comparable with those of the trochoidal motion in the observation. These suggest that, in tropical cyclones with the concentric eyewall structure, the interaction of an asymmetric double vortex can become a cause of trochoidal motion.

scholarly journals Comments on “Revisiting the Relationship between Eyewall Contraction and Intensification”

2017 ◽  
Vol 74 (12) ◽  
pp. 4265-4274 ◽  
Author(s):  
Chanh Q. Kieu ◽  
Da-Lin Zhang
Keyword(s):  
Tropical Cyclone ◽  
Tropical Cyclones ◽  
Governing Equation ◽  
Directional Derivative ◽  
Maximum Wind ◽  
The Relationship ◽  
Derivative Concept

Abstract This comment presents some concerns with the study of Stern et al. and their misinterpretation of the contraction of the radius of the maximum wind (RMW) in tropical cyclones. It is shown that their geometrical RMW contraction model provides little dynamical understanding of the RMW contraction during tropical cyclone intensification, and it differs fundamentally from the RMW contraction model of Willoughby et al. that was derived from the directional derivative concept. Moreover, it is demonstrated that Stern et al. were mistaken in commenting on the derivation of the governing equation for the RMW contraction in Kieu.

The Relationship between Tropical Cyclone Intensity Change and the Strength of Inner-Core Convection

2012 ◽  
Vol 140 (4) ◽  
pp. 1164-1176 ◽  
Author(s):  
Haiyan Jiang
Keyword(s):  
Tropical Cyclone ◽  
Brightness Temperature ◽  
Inner Core ◽  
Cumulative Distribution ◽  
Intensity Change ◽  
Sample Mean ◽  
Convective Parameter ◽  
Significant Difference ◽  
Radar Echo ◽  
The Relationship

Convective intensity proxies measured by the Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI), Precipitation Radar (PR), and Visible and Infrared Scanner (VIRS) are used to assess the relationship between intense convection in the inner core and tropical cyclone (TC) intensity change. Using the cumulative distribution functions of 24-h intensity changes from the 1998–2008 best-track data for global TCs, five intensity change categories are defined: rapidly intensifying (RI), slowly intensifying, neutral, slowly weakening, and rapidly weakening. TRMM observations of global TCs during 1998–2008 are used to generate the distributions of convective properties in the storm’s inner-core region for different storm intensity change categories. To examine the hypothesis of hot towers near the eye as an indicator of RI, hot towers are defined by precipitation features with 20-dBZ radar echo height reaching 14.5 km. The differences in the convective parameters between rapidly intensifying TCs and slowly intensifying, neutral, slowly weakening, and rapidly weakening TCs are quantified using statistical analysis. It is found that statistically significant differences of three out of four convective intensity parameters in the inner core exist between RI and non-RI storms. Between RI and slowly intensifying TCs, a statistically significant difference exists for the minimum 11-μm IR brightness temperature TB11 in the inner core. This indicates that a relationship does exist between inner-core convective intensity and TC intensity change. The results in this study also suggest that the rate of intensification appears to be influenced by convective activity in the inner core and the ability to predict RI might be further improved by using convective parameters. With regard to different convective proxies, the relationships are different. The minimum TB11, upper-level maximum radar reflectivities, and maximum 20-dBZ radar echo height in the inner core are best associated with the rate of TC intensity change, while the minimum 85-GHz polarization corrected brightness temperature (PCT) shows some ambiguities in relation to intensity change. The minimum 37-GHz PCT shows no significant relationship with TC intensity change, probably because of the contamination of the ice scattering signal by emission from rain and liquid water in this channel. By examining the probability of RI for each convective parameter for which statistically significant differences at the 95% level were found of RI and non-RI cases, it is found that all three parameters provide additional information relative to climatology. The most skillful parameter is minimum TB11, and the second is maximum 20-dBZ height, followed by minimum 85-GHz PCT. However, the increases of RI probability from the larger sample mean by using these predictors are not very large. When using the existence of hot towers as a predictor, it is found that the probabilities of RI and slowly intensifying increase and those of slowly weakening and rapidly weakening decrease for samples with hot towers in the inner core. However, the increases for intensifying and decreases for weakening are not substantial, indicating that hot towers are neither a necessary nor a sufficient condition for RI.

Retroaktive Neuverhandlung

2018 ◽  
Vol 63 (1) ◽  
Author(s):  
Daniel Martin Feige
Keyword(s):  
Original Work ◽  
The Other ◽  
Final Part ◽  
Critical Reading ◽  
The Third ◽  
Works Of Art ◽  
The Relationship

Der Beitrag widmet sich der Frage historischer Folgeverhältnisse in der Kunst. Gegenüber dem Gedanken, dass es ein ursprüngliches Werk in der Reihe von Werken gibt, das späteren Werken seinen Sinn gibt, schlägt der Text vor, das Verhältnis umgekehrt zu denken: Im Lichte späterer Werke wird der Sinn früherer Werke neu ausgehandelt. Dazu geht der Text in drei Schritten vor. Im ersten Teil formuliert er unter der Überschrift ›Form‹ in kritischer Abgrenzung zu Danto und Eco mit Adorno den Gedanken, dass Kunstwerke eigensinnig konstituierte Gegenstände sind. Die im Gedanken der Neuverhandlung früherer Werke im Lichte späterer Werke vorausgesetzte Unbestimmtheit des Sinns von Kunstwerken wird im zweiten Teil unter dem Schlagwort ›Zeitlichkeit‹ anhand des Paradigmas der Improvisation erörtert. Der dritte und letzte Teil wendet diese improvisatorische Logik unter dem Label ›Neuaushandlung‹ dann dezidiert auf das Verhältnis von Vorbild und Nachbild an. The article proposes a new understanding of historical succession in the realm of art. In contrast to the idea that there is an original work in the series of works that gives meaning to the works that come later, the text proposes to think it exactly the other way round: in the light of later works, the meanings of earlier works are renegotiated. The text proceeds in three steps to develop this idea. Under the heading ›Form‹ it develops in the first part a critical reading of Danto’s and Eco’s notion of the constitution of the artworks and argues with Adorno that each powerful work develops its own language. In the second part, the vagueness of the meaning of works of art presupposed in the idea of renegotiating earlier works in the light of later works is discussed under the term ›Temporality‹ in terms of the logic of improvisation. The third and final part uses this improvisational logic under the label ›Renegotiation‹ to understand the relationship between model and afterimage in the realm of art.

RECREATION SPECIALIZATION FOR RUNNERS AND EVENT ATTACHMENT

2020 ◽  
Author(s):  
Isao Okayasu ◽  
Chi-Ok Oh ◽  
Duarte B Morais
Keyword(s):  
Practical Implication ◽  
Event Management ◽  
Attitudes And Behaviors ◽  
The Third ◽  
Study Results ◽  
The World ◽  
Recreation Specialization ◽  
And Behaviors ◽  
The Relationship ◽  
Predictive Relationship

Running is one of the most popular activities in the world. Runners’ attitudes and behaviors vary depending on their running style. This study aims to construct different measures of running specialization based on the theory of specialization. This study also tests a runner’s stage of specialization segmentation based on recreation specialization and examines the predictive relationship between a runner’s specialization and event attachment. Three groups of sampling data assess the performance of diverse specialization measures for running in three marathon events. First, two surveys were conducted with marathon participants to assess the performance of diverse specialization measures for runners. Second, the third dataset was used to examine the relationship between a runner’s recreation specialization and event attachment.The study results showed that the 15 measures of specialization showed a good fit to the data. Our research showed how runners’ recreation specialization is connected to their event attachment. In addition, this study suggested event management for subdivisions of runners. Its practical implication is that recreation specialization for running can help us understand event attachment.

scholarly journals Engine Malfunctioning Conditions Identification through Instantaneous Crankshaft Torque Measurement Analysis

2021 ◽  
Vol 11 (8) ◽  
pp. 3522
Author(s):  
Konstantinos-Marios Tsitsilonis ◽  
Gerasimos Theotokatos
Keyword(s):  
Operating Conditions ◽  
Cylinder Pressure ◽  
Dynamics Model ◽  
Engine Model ◽  
Measurement Analysis ◽  
Start Of Injection ◽  
Rate Of Heat Release ◽  
Relationship Of ◽  
Diagnostic Measurement ◽  
The Relationship

In this study a coupled thermodynamics and crankshaft dynamics model of a large two-stroke diesel engine was utilised, to map the relationship of the engine Instantaneous Crankshaft Torque (ICT) with the following frequently occurring malfunctioning conditions: (a) change in Start of Injection (SOI), (b) change in Rate of Heat Release (RHR), (c) change in scavenge air pressure, and (d) blowby. This was performed using frequency analysis on the engine ICT, which was obtained through a series of parametric runs of the coupled engine model, under the various malfunctioning and healthy operating conditions. This process demonstrated that engine ICT can be successfully utilised to identify the distinct effects of malfunctions (c) or (d), as they occur individually in any cylinder. Furthermore by using the same process, malfunctions (a) and (b) can be identified as they occur individually for any cylinder, however there is no distinct effect on the engine ICT among these malfunctions, since their effect on the in-cylinder pressure is similar. As a result, this study demonstrates the usefulness of the engine ICT as a non-intrusive diagnostic measurement, as well as the benefits of malfunctioning conditions mapping, which allows for quick and less resource intensive identification of engine malfunctions.

scholarly journals Analyzing the Effects of the Kinematic System on the Quality of Holes Drilled in 42CrMo4 + QT Steel

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4046
Author(s):  
Mateusz Bronis ◽  
Edward Miko ◽  
Lukasz Nowakowski
Keyword(s):  
Cutting Speed ◽  
Hole Drilling ◽  
Internal Cooling ◽  
Hole Quality ◽  
The Third ◽  
Kinematic System ◽  
Turning Center ◽  
Dimensional Errors ◽  
The Relationship

This article discusses the relationship between the kinematic system used in drilling and the quality of through-holes. The drilling was done on a CTX Alpha 500 universal turning center using a TiAlN-coated 6.0 mm drill bit with internal cooling, mounted in a driven tool holder. The holes were cut in cylindrical 42CrMo4 + QT steel samples measuring 30 mm in diameter and 30 mm in length. Three types of hole-drilling kinematic systems were considered. The first consisted of a fixed workpiece and a tool performing rotary (primary) and linear motions. In the second system, the workpiece rotated (primary motion) while the tool moved linearly. In the third system, the workpiece and the tool rotated in opposite directions; the tool also moved linearly. The analysis was carried out for four output parameters characterizing the hole quality (i.e., cylindricity, straightness, roundness, and diameter errors). The experiment was designed using the Taguchi approach (orthogonal array). ANOVA multi-factor statistical analysis was used to determine the influence of the input parameters (cutting speed, feed per revolution and type of kinematic system) on the geometrical and dimensional errors of the hole. From the analysis, it is evident that the kinematic system had a significant effect on the hole roundness error.

scholarly journals Tropical cyclone simulations over Bangladesh at convection permitting 4.4 km & 1.5 km resolution

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Hamish Steptoe ◽  
Nicholas Henry Savage ◽  
Saeed Sadri ◽  
Kate Salmon ◽  
Zubair Maalick ◽  
...  
Keyword(s):  
Wind Speed ◽  
Tropical Cyclone ◽  
Sea Level ◽  
Tropical Cyclones ◽  
Weather Forecasting ◽  
Sea Level Pressure ◽  
Mean Sea Level ◽  
Level Pressure ◽  
Medium Range ◽  
Gust Speed

AbstractHigh resolution simulations at 4.4 km and 1.5 km resolution have been performed for 12 historical tropical cyclones impacting Bangladesh. We use the European Centre for Medium-Range Weather Forecasting 5th generation Re-Analysis (ERA5) to provide a 9-member ensemble of initial and boundary conditions for the regional configuration of the Met Office Unified Model. The simulations are compared to the original ERA5 data and the International Best Track Archive for Climate Stewardship (IBTrACS) tropical cyclone database for wind speed, gust speed and mean sea-level pressure. The 4.4 km simulations show a typical increase in peak gust speed of 41 to 118 knots relative to ERA5, and a deepening of minimum mean sea-level pressure of up to −27 hPa, relative to ERA5 and IBTrACS data. The downscaled simulations compare more favourably with IBTrACS data than the ERA5 data suggesting tropical cyclone hazards in the ERA5 deterministic output may be underestimated. The dataset is freely available from 10.5281/zenodo.3600201.

scholarly journals The Correlation Between Timing of Surgery and the Need for RBC Transfusions in the Geriatric Intertrochanteric Fracture Population

2021 ◽  
Vol 12 ◽  
pp. 215145932199861
Author(s):  
Yun-fa Yang ◽  
Jian-wen Huang ◽  
Xiao-sheng Gao ◽  
Zai-li Liu ◽  
Jian-wei Wang ◽  
...  
Keyword(s):  
Intertrochanteric Fracture ◽  
The Elderly ◽  
Timing Of Surgery ◽  
Intertrochanteric Fractures ◽  
The Third ◽  
Transfusion Requirements ◽  
Surgical Fixation ◽  
Fracture Population ◽  
The Relationship ◽  
Rbc Transfusion

Objective: To identify whether the timing of surgery affects red blood cell (RBC) transfusion requirements in the elderly with intertrochanteric fractures. Methods: We retrospectively studied all patients undergoing surgical fixation of their intertrochanteric fractures in our hospital between January 2009 and December 2018 and analyzed the relationship between the timing of surgery and RBC transfusion. Results: A total of 679 patients were included in this study. The need for RBC transfusion was lower in the patients who underwent surgery within 12 h after admission (timing of surgery <12 h, <12 h group) than those who underwent surgery over 12 h after admission (timing of surgery >12 h, >12 h group) (P = 0.046); lower in the the patients who underwent surgery within 24 h after admission (timing of surgery <24 h, <24 h group) than in those who underwent surgery over 24 h after admission (timing of surgery >24 h, >24 h group) (P = 0.008), and lower in the <24 h group compared to the patients who underwent surgery within 48 h after admission (timing of surgery <48 h, <48 h group) (P = 0.035). Moreover, the need for RBC transfusion was lower in the <24 h group (in the first 24 h from admission to surgery) than in the 24-48 h group (in the second 24 h from admission to surgery) (P = 0.016), and also lower in the <24 h group compared to the 48-72 h group (in the third 24 h from admission to surgery) (P = 0.047). However, there were no differences between the <12 h group and 12-24 h group, between the <12 h group and <24 h group, and between the 12-24 h group and <24 h group, respectively. Conclusion: Timing of surgery within 24 h contributes to the reduction of RBC transfusion in the elderly with intertrochanteric fractures.

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