Discharge of a Compressible Fluid Through a Control Valve

1987 ◽  
Vol 54 (4) ◽  
pp. 955-960 ◽  
Author(s):  
Z. M. Weng ◽  
Alice A. L. Ting ◽  
W. L. Chow
Keyword(s):  
Compressible Fluid ◽  
Control Valve ◽  
Supercritical Pressure ◽  
Special Treatment ◽  
Ample Evidence ◽  
Flow Discharge ◽  
Free Jet ◽  
Sonic Line ◽  
Original Analysis ◽  
Hodograph Transformation

The original analysis on incompressible flow discharge from a vessel through an axisymmetric control valve has been extended to the discharge of a compressible fluid. The inviscid anlaysis is based on the method of hodograph transformation. While it is simple to account for the effect of compressibility for conditions of subcritical pressure ratios, special treatment must be applied to establish the sonic line and the free jet boundaries under conditions of supercritical pressure ratios. Discharge characteristics have been established for different pressure ratios and positions of the control valve. This series of investigations provides ample evidence that the hodograph transformation coupled with numerical computations is effective in dealing with problems of this nature.

Gravitational Flow Discharge From a Horizontal Duct

1985 ◽  
Vol 52 (1) ◽  
pp. 167-171 ◽  
Author(s):  
P. Chan ◽  
T. Han ◽  
W. L. Chow
Keyword(s):  
Initial Pressure ◽  
Unknown Boundary ◽  
Physical Plane ◽  
Flow Discharge ◽  
Free Jet ◽  
Gravitational Flow ◽  
Total Head ◽  
Boundary Functions ◽  
Hodograph Plane ◽  
Hodograph Transformation

The problem of a potential flow discharge through a two-dimensional horizontal duct under the influence of gravitation is examined by the method of hodograph transformation. The stream function is considered and established in the hodograph plane, and the solution in the physical plane is established through additional integrations. The unknown boundary functions of the free jet must be determined as part of the solution. The initial pressure level and the discharge characteristics between the total head and the flow rate, have been established. Results are compared with those obtained previously by other method.

Discharge From a Vessel Through an Axisymmetric Control Valve

1987 ◽  
Vol 54 (2) ◽  
pp. 447-452 ◽  
Author(s):  
W. L. Chow ◽  
Alice A. L. Ting ◽  
P. H. Tsai
Keyword(s):  
Boundary Value Problem ◽  
Numerical Computation ◽  
Incompressible Flow ◽  
Boundary Value ◽  
Control Valve ◽  
Unusual Feature ◽  
Flow Discharge ◽  
Hodograph Plane ◽  
Hodograph Transformation

The problem of an incompressible flow discharge through an axisymmetric control valve has been examined through the method of hodograph transformation. The boundary value problem in the hodograph plane has an unusual feature in that part of the boundary is overlapped. Certain manipulations have been applied to produce the realistic free streamline configuration. The rate of discharge is obtained for various locations of the valve. This investigation provides the evidence that the method of hodograph transformation coupled with numerical computation is indeed effective in dealing with problems of this kind.

Focusing effects in two-dimensional, supersonic flow

1949 ◽  
Vol 242 (844) ◽  
pp. 153-171 ◽  
Keyword(s):  
Method Of Characteristics ◽  
Inverse Transformation ◽  
Two Dimensional ◽  
Perfect Gas ◽  
Geometrical Method ◽  
Independent Variables ◽  
Flow Problems ◽  
Sonic Line ◽  
Hodograph Transformation ◽  
Line Patterns

The steady, supersonic, irrotational, isentropic, two-dimensional, shock-free flow of a perfect gas is investigated by a new, geometrical, method based on the use of characteristic co-ordinates. Some of the results apply also to more general problems of compressible flow involving two independent variables (§1). The method is applied in particular to the treatment of the non-linear, non-analytic features. The variation in magnitude of discontinuities of the velocity gradient is determined as a function of the Mach number in § 4. The reflexion at the sonic line of such discontinuities is treated in § 7. The isingularities of the field of flow are discussed in §§ 5 to 5.4; Craggs’s (1948) results are extended to the case when the velocity components are not analytic functions of position, and to the case in which both the hodograph transformation and the inverse transformation are singular.. Examples are given of singularities that occur in familiar flow problems, but have not hitherto been described (§§ 5.3, 5.4). Some properties are established of the geometry in the large of Mach line patterns; these properties are useful for the prediction of limit lines (§ 5.2). The problem of the start of an oblique shockwave in the middle of the flow is briefly reviewed in §6. In the appendix it is shown that the conventional method of characteristics for the numerical treat­ ment of two-dimensional, isentropic, irrotational, steady, supersonic flows must be modified near a branch line if a loss of accuracy is to be avoided.

Bears

2020 ◽  
Keyword(s):  
Native American ◽  
North America ◽  
Special Treatment ◽  
Ample Evidence ◽  
Native Peoples ◽  
Atlantic Trade ◽  
Economic Significance ◽  
Northern Latitudes ◽  
Comparative Ethnography ◽  
Native North America

Thanks to Irving Hallowell’s classic 1926 comparative ethnography on the special mythic status of bears in Subarctic cultures, anthropologists are generally aware that peoples throughout the northern hemisphere have treated bears as far more than a subsistence resource, something more akin to another kind of human or, to use Hallowell’s famous phrase, “other-than-human persons.” While Hallowell provided ample evidence of bear ceremonialism in northern latitudes, he found little evidence for the special treatment of bears elsewhere in Native North America. Archaeological and historical research over the last nine decades, however, has produced vast unsynthesized information about the roles of bears in Native American beliefs, rituals, and subsistence. This book is the first collective effort since Hallowell’s formative publication to consider how Native peoples viewed, treated, and used black bears (Ursus americanus) through time across Eastern North America. Contributors draw on zooarchaeological, ethnohistorical, ethnographic, and other evidence of bear hunting, consumption, and use, while contemplating the range of relationships that existed between bears and humans. They have reviewed thousands of pages of ethnohistorical and ethnographic documents and summarized and interpreted data on bear remains from nearly 300 archaeological sites from Quebec to the Gulf of Mexico. Native peoples perceived and related to bears in remarkably diverse ways. Our authors explore the religious and economic significance of bears and bear products (meat, fat, oil, pelts, etc.), bear imagery in Native art and artifacts, and bears in Native worldviews, kinship systems, and cosmologies, along with their role as exported commodities in trans-Atlantic trade.

scholarly journals Design of A Streamwise-Lateral Ski-Jump Flow Discharge Spillway

Water ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1585 ◽  
Author(s):  
Jun Deng ◽  
Wangru Wei ◽  
Zhong Tian ◽  
Faxing Zhang
Keyword(s):  
Side Wall ◽  
Hydraulic Engineering ◽  
Limited Area ◽  
Lateral Direction ◽  
Flow Discharge ◽  
Free Jet ◽  
Plunge Pool ◽  
New Type ◽  
Solid Walls ◽  
Large Discharge

Spillway outlet design is a major issue in hydraulic engineering with high head and large discharge conditions. A new type of design for a streamwise-lateral spillway is proposed for ski-jump flow discharge and energy dissipation in hydraulic engineering. The water in the spillway outlet is constrained by three solid walls with an inclined floor, a horizontal floor on the bottom and a deflected side wall in the lateral direction. The water flow releases in a lateral direction into the plunge pool along the streamwise direction. It generates a free jet in the shape of “∩” in a limited area, causing the water to fully diffuse and stretch in the air simultaneously, and drop into the plunge pool to avoid excessive impact in the plunge pool. The formation mechanism for the flow pattern is analyzed, and the results show that the optimum inclination is an angle range of 30°~45° for a good performance of free ski-jump jet diffusion shape.

The breakdown of the hodograph transformation for irrotational compressible fluid flow in two dimensions

1948 ◽  
Vol 44 (3) ◽  
pp. 360-379 ◽  
Author(s):  
J. W. Craggs
Keyword(s):  
Fluid Flow ◽  
Shock Waves ◽  
Compressible Fluid ◽  
Equations Of Motion ◽  
Two Dimensions ◽  
Compressible Fluid Flow ◽  
Hodograph Plane ◽  
Hodograph Transformation

It has been noticed by various authors that the use of the hodograph transformation for problems of compressible fluid flow leads to flows having singularities where the acceleration becomes infinite, streamlines have cusps and the solution of the equations of motion in the hodograph plane ceases to represent any possible physical flow. In this paper we investigate the nature of the singularities which can occur in the representation of one plane upon another and apply our results to the hodograph transformation. Finally, we discuss the significance for practical purposes of such singularities and in particular their connexion with the occurrence of shock waves.

scholarly journals A.F. Losev on F.M. Dostoevsky. About Losev's Activity in the Literary Section of the GAKhN

2021 ◽  
Vol 25 (1) ◽  
pp. 89-102
Author(s):  
Giorgia Rimondi
Keyword(s):  
Comprehensive Evaluation ◽  
Special Treatment ◽  
Ample Evidence ◽  
Special Regard ◽  
Russian Philosopher ◽  
Ancient Literature ◽  
Symbolic Images

The researcher scrutinizes one peculiar historical and philosophical fact which has been generally overlooked when studying Dostoevsky. The analysis of the writer's works was carried out by the outstanding Russian philosopher Aleksei Losev at the Russian Academy of Artistic Sciences (GAKhN). The article also provides further information on Losev's work at the Academy in the 1920s. Special regard is paid to the Russian philosopher's activities in the Literary Section in 1927-1929 (in the group on Ancient Literature, in the Commission for the Study of Dostoevsky). The author provides ample evidence of the special treatment Losev paid to Dostoevsky, including numerous discussions of reports on the Russian writer's oeuvre. The article draws attention to the fact that the main focus of Losev's analysis of Dostoevsky was the writer's symbolism. It is noted that Losev turned to the study of such as early as in the 1920s. However, the philosopher managed to publish his findings much later. According to Losev, symbolic images pervade all of Dostoevsky's works. Based on the comprehensive evaluation of archival sources (recorded in the minutes of meetings, preserved at the Academy) and their comparison, the article unveils a picture of the Russian philosopher's activity and agenda. That helps us better grasp the range of his scholarly interests, significantly expands the opportunities for further research into this period of Losev's life and provides new data for the GAKhN history.

Modeling and HIL Simulation of Flight Conditions Simulating Control System for the Altitude Test Facility

2016 ◽  
Vol 33 (4) ◽  
Author(s):  
Jun Zhou ◽  
Li Shen ◽  
Tianhong Zhang
Keyword(s):  
Control System ◽  
Wind Tunnel Test ◽  
Control Valve ◽  
Simulation System ◽  
Test Facility ◽  
Engine Test ◽  
Simulated Altitude ◽  
Free Jet ◽  
Aero Engine ◽  
Hil Simulation

AbstractSimulated altitude test is an essential exploring, debugging, verification and validation means during the development of aero-engine. Free-jet engine test can simulate actual working conditions of aero-engine more realistically than direct-connect engine test but with relatively lower cost compared to propulsion wind tunnel test, thus becoming an important developing area of simulated altitude test technology. The Flight Conditions Simulating Control System (FCSCS) is of great importance to the Altitude Test Facility (ATF) but the development of that is a huge challenge. Aiming at improving the design efficiency and reducing risks during the development of FCSCS for ATFs, a Hardware- in-the-Loop (HIL) simulation system was designed and the mathematical models of key components such as the pressure stabilizing chamber, free-jet nozzle, control valve and aero-engine were built in this paper. Moreover, some HIL simulation experiments were carried out. The results show that the HIL simulation system designed and established in this paper is reasonable and effective, which can be used to adjust control parameters conveniently and assess the software and hardware in the control system immediately.

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