A methodology for development of software composite-metrics for program control-flow structure

1992 ◽  
Vol 7 (3) ◽  
pp. 202-218 ◽  
Author(s):  
Aftab Ahmad
Keyword(s):  
Flow Structure ◽  
Control Flow ◽  
Program Control

Numerical Investigation of Passive Flow Control Using Wavy Blades in a Highly-Loaded Compressor Cascade

2018 ◽  
Author(s):  
Bo Wang ◽  
Yanhui Wu ◽  
Kai Liu
Keyword(s):  
Numerical Investigation ◽  
Flow Structure ◽  
Cross Flow ◽  
Leading Edge ◽  
Control Flow ◽  
Streamwise Vortices ◽  
Compressor Cascade ◽  
Control Effect ◽  
Suction Surface ◽  
Highly Loaded

Driven by the need to control flow separations in highly loaded compressors, a numerical investigation is carried out to study the control effect of wavy blades in a linear compressor cascade. Two types of wavy blades are studied with wavy blade-A having a sinusoidal leading edge, while wavy blade-B having pitchwise sinusoidal variation in the stacking line. The influence of wavy blades on the cascade performance is evaluated at incidences from −1° to +9°. For the wavy blade-A with suitable waviness parameters, the cascade diffusion capacity is enhanced accompanied by the loss reduction under high incidence conditions where 2D separation is the dominant flow structure on the suction surface of the unmodified blade. For well-designed wavy blade-B, the improvement of cascade performance is achieved under low incidence conditions where 3D corner separation is the dominant flow structure on the suction surface of the baseline blade. The influence of waviness parameters on the control effect is also discussed by comparing the performance of cascades with different wavy blade configurations. Detailed analysis of the predicted flow field shows that both the wavy blade-A and wavy blade-B have capacity to control flow separation in the cascade but their control mechanism are different. For wavy blade-A, the wavy leading edge results in the formation of counter-rotating streamwise vortices downstream of trough. These streamwise vortices can not only enhance momentum exchange between the outer flow and blade boundary layer, but also act as the suction surface fence to hamper the upwash of low momentum fluid driven by cross flow. For wavy blade-B, the wavy surface on the blade leads to a reduction of the cross flow upwash by influencing the spanwise distribution of the suction surface static pressure and guiding the upwash flow.

DEVELOPING ALGORITHM FOR PARTITIONING TASKS INTO SUBTASKS IN THE SYSTEMS OF DISTRIBUTED DATA PROCESSING

2017 ◽  
pp. 31-38
Author(s):  
Vladislav Vladislavovich Lukashenko ◽  
Vitaly Aleksandrovich Romanchuk
Keyword(s):  
Clock Cycle ◽  
Control Flow ◽  
Program Control ◽  
Distributed Data ◽  
Control Flow Graph ◽  
Abstract Syntax ◽  
Flow Graph ◽  
Abstract Syntax Tree ◽  
Syntax Tree ◽  
Computational Cluster

In terms of the problem of insufficient computational resources for a number of tasks, realization of computational cluster of neurocomputers is being considered as a variant. To implement the basic principle of distributed computing, there has been presented an algorithm for splitting the tasks entering the computational cluster of neurocomputers into sub-tasks. For this purpose, the program introduced into the cluster is suggested to present for execution in the modified postfix Polish record and to store it in the program command stack. To modify the program Polish notation should include different, non-arithmetic, operators and constructions. The next step is to get an abstract syntax tree of the program, following the rules for translating the modified postfix Polish record from the command stack into an abstract syntax tree. Then, the data should be sent to the abstract syntax tree of the program taking into account their bit depth, and to obtain the contiguity matrix of the program control flow graph that will display the set of all ways of program execution. The authors come to the conclusion that all operations recorded in the modified reverse Polish record presented in the form of an abstract syntax tree when data of a certain bit depth are transmitted to them, at the moment of transition to the program control flow graph executed in a single clock cycle are indivisible operations and can be represented as subprograms of the source program, which was submitted for processing to the computer cluster of neurocomputers.

Three-dimensional numerical study of flow structure in channel confluences

2010 ◽  
Vol 37 (5) ◽  
pp. 772-781 ◽  
Author(s):  
Ahmad Shakibainia ◽  
Mohammad Reza Majdzadeh Tabatabai ◽  
Amir Reza Zarrati
Keyword(s):  
Froude Number ◽  
Flow Structure ◽  
Flow Separation ◽  
Water Surface ◽  
Numerical Study ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
River System ◽  
Control Flow ◽  
Secondary Currents

Channel confluence is one of the important features of each river system and some hydraulic structures. The features that can dominantly control flow characteristics in a confluence are confluence angle, discharge, width ratios, and Froude number of flow. Several research studies have been conducted however a comprehensive three-dimensional (3-D) numerical study of flow characteristics in a confluence has not yet been reported. In the present study, SSIIM2.0, a 3-D numerical model, is validated and applied to investigate secondary currents, velocity distribution, flow separation, and water surface elevation in different conditions. The results of the present study illustrate that flow structure and water surface variations in a confluence are highly influenced by confluence angle, discharge, and width ratios as well as Froude number because of their effect on flow deflection, separation, and secondary currents. The graphs from the present study can be used to analyze water surface variation, velocity field, and flow separation dimensions in difference conditions for engineering designs.

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