scholarly journals Bow and Stern Control Surface’s Effectiveness and Influence on Supercavity

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Ping Wei ◽  
Wenrong Yan ◽  
Shoufa Wang ◽  
Xin Yu
Keyword(s):  
Control Mode ◽  
Joint Control ◽  
Multiphase Model ◽  
Cavitation Model ◽  
Research Results ◽  
Supercavitating Vehicle ◽  
Supercavitating Flow ◽  
Numerical Research ◽  
Control Surfaces ◽  
Rudder Angle

The numerical model of supercavitating flow field was established based on multiphase model, cavitation model, and turbulence model. The model was employed to simulate the supercavitation flow for the supercavitating vehicle with two types of control surfaces: bow rudder and stern rudder. The influence of both control surfaces on the supercavity shape and rudder effectiveness is compared under the different rudder angles (0-12°), and the effectiveness and the influences on supercavities of bow rudder and stern rudder were explored according to the numerical research results. From the research results, the following conclusions can be drawn: (1) the bow rudders have stable rudder effectiveness and available rudder angle, and the bow rudders also have significant influence on supercavities’ shape. (2) By contrast with the bow rudder, stern rudders’ effectiveness is difficult to predict accurately, and the phenomenon of stalling will occur when stern rudders’ rudder angle exceeds 6°; however, there is almost no influence of stern rudders on supercavities. (3) The bow and stern rudders joint control mode must take the influence on supercavities’ shape and the accuracy of control force’s forecasting into account at the same time. The research is helpful to the optimizing of superhigh-speed vehicles and the design of control modes.

Heading control of a novel finless high-speed supercavitating vehicle with an internal oscillating pendulum

2020 ◽  
pp. 107754632094834
Author(s):  
Mojtaba Mirzaei ◽  
Hossein Taghvaei
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Sliding Mode ◽  
Six Degrees Of Freedom ◽  
Supercavitating Vehicles ◽  
Supercavitating Vehicle ◽  
High Speeds ◽  
Heading Control ◽  
Heading Angle ◽  
Control Surfaces

High-speed supercavitating vehicles are surrounded by a huge cavity of gas and only a small portion of the nose and the tail of the vehicle are in contact with the water which leads to a considerable reduction in skin friction drag and reaching very high speeds. High-speed supercavitating vehicles are usually controlled by the cavitator at the nose which controls the pitch and depth of the vehicle and the control surfaces or fins which control the roll and heading angle of the vehicle using the bank-to-turn maneuvering method. However, control surfaces have disadvantages such as the high drag force and ineffectiveness due to the supercavity. Therefore, the purpose of the present study is to eliminate the fins from high-speed supercavitating vehicles and propose a new bank-to-turn heading control of this novel finless high-speed supercavitating vehicle which is composed of the cavitator at the nose and an oscillating pendulum as the internal actuator. Sliding mode control as a robust method is used for the six-degrees-of-freedom model of this finless high-speed vehicle against exposed disturbances. Some design criteria for the design of the internal pendulum in this finless supercavitating vehicle are presented for the damping coefficient, pendulum mass, and radius.

scholarly journals A Joint Control Model Based on Emission Rights Futures Trading for Regional Air Pollution That Accounts for the Impacts on Employment

2019 ◽  
Vol 11 (21) ◽  
pp. 5894 ◽  
Author(s):  
Wang ◽  
Zhao ◽  
Yang ◽  
Wang ◽  
Xue ◽  
...  
Keyword(s):  
Air Pollution ◽  
Pollution Control ◽  
Control Model ◽  
Air Pollutant ◽  
Control Mode ◽  
Spot Price ◽  
Joint Control ◽  
Air Pollution Control ◽  
Futures Trading ◽  
Emission Rights

To reduce air pollutant control costs and solve the problem of decreased employment caused by air pollution control, we established a double-objective optimization Joint Control Model (JCM) based on emission rights futures trading. The JCM calculates the spot price of emission rights, classifies regions in the trading market for emission rights into buyers and sellers, and calculates the optimal cooperative pollution abatement quantity. Compared with a non-cooperative control mode, the JCM generated benefits of US$2485.19 × 106. We then used a Game Quadratic Programming (GQP) method to distribute the benefits, and applied the JCM to a case study of the abatement of sulfur dioxide in China’s Shanxi, Henan, and Shaanxi provinces. We found that: (i) Compared with a JCM that does not account for employment, employment under the JCM increased by 3.20 × 103 people, and the pollution control cost decreased by US$11.20 × 106 under the JCM that considered employment. The effect of the latter model is better than that of the former. (ii) Employment under the JCM increased by 18.80 × 104 people compared with that under a territorial control mode, reducing the cost by US$99.73 × 106. The JCM is helpful for all participating regions to balance environmental and livelihood issues in the process of air pollution control to achieve sustainable development.

07.37: Development in calculation of stressed skin effect upon experimental and numerical research results

ce/papers ◽  
2017 ◽  
Vol 1 (2-3) ◽  
pp. 1812-1821
Author(s):  
Anita Lendvai ◽  
Attila László Joó
Keyword(s):  
Skin Effect ◽  
Research Results ◽  
Numerical Research

Role of Proprioceptive Signals From an Insect Femur-Tibia Joint in Patterning Motoneuronal Activity of an Adjacent Leg Joint

1999 ◽  
Vol 81 (4) ◽  
pp. 1856-1865 ◽  
Author(s):  
Dietmar Hess ◽  
Ansgar Büschges
Keyword(s):  
Movement Control ◽  
Stick Insect ◽  
Control Mode ◽  
Chordotonal Organ ◽  
Joint Control ◽  
Muscarinic Agonist ◽  
Behavioral State ◽  
Sensory Signals ◽  
Motoneuron Activity

Role of proprioceptive signals from an insect femur-tibia joint in patterning motoneuronal activity of an adjacent leg joint. Interjoint reflex function of the insect leg contributes to postural control at rest or to movement control during locomotor movements. In the stick insect ( Carausius morosus), we investigated the role that sensory signals from the femoral chordotonal organ (fCO), the transducer of the femur-tibia (FT) joint, play in patterning motoneuronal activity in the adjacent coxa-trochanteral (CT) joint when the joint control networks are in the movement control mode of the active behavioral state. In the active behavioral state, sensory signals from the fCO induced transitions of activity between antagonistic motoneuron pools, i.e., the levator trochanteris and the depressor trochanteris motoneurons. As such, elongation of the fCO, signaling flexion of the FT joint, terminated depressor motoneuron activity and initiated activity in levator motoneurons. Relaxation of the fCO, signaling extension of the FT joint, induced the opposite transition by initiating depressor motoneuron activity and terminating levator motoneuron activity. This interjoint influence of sensory signals from the fCO was independent of the generation of the intrajoint reflex reversal in the FT joint, i.e., the “active reaction,” which is released by elongation signals from the fCO. The generation of these transitions in activity of trochanteral motoneurons barely depended on position or velocity signals from the fCO. This contrasts with the situation in the resting behavioral state when interjoint reflex action markedly depends on actual fCO stimulus parameters, i.e., position and velocity signals. In the active behavioral state, movement signals from the fCO obviously trigger or release centrally generated transitions in motoneuron activity, e.g., by affecting central rhythm generating networks driving trochanteral motoneuron pools. This conclusion was tested by stimulating the fCO in “fictive rhythmic” preparations, activated by the muscarinic agonist pilocarpine in the otherwise isolated and deafferented mesothoracic ganglion. In this situation, sensory signals from the fCO did in fact reset and entrain rhythmic activity in trochanteral motoneurons. The results indicate for the first time that when the stick insect locomotor system is active, sensory signals from the proprioceptor of one leg joint, i.e., the fCO, pattern motor activity in an adjacent leg joint, i.e., the CT joint, by affecting the central rhythm generating network driving the motoneurons of the adjacent joint.

The Numerical Research on the Scramjet Combustion with Different Structure Cavity

2012 ◽  
Vol 468-471 ◽  
pp. 1444-1447 ◽  
Author(s):  
Peng Gao ◽  
Xin Long Chang ◽  
Lei Luo ◽  
Yu Ji Cao
Keyword(s):  
Numerical Simulations ◽  
Combustion Chamber ◽  
Fuel Combustion ◽  
Hydrogen Fuel ◽  
Mixed Fuel ◽  
Research Results ◽  
Numerical Research

In this paper, the detailed numerical simulations were performed in the hydrogen fuel combustion chamber with some different structure cavities. Through the analysis found that the effect of stabilized fire burning at supersonic flowing and mixed fuel and air are quite different. The research results will preferably represent the burning field in scramjet combustion so that the better performance flame stabilizer can be designed.

scholarly journals NUMERICAL STUDY OF UNSTEADY SUPERCAVITATION PERTURBED BY A PRESSURE WAVE

2016 ◽  
Vol 42 ◽  
pp. 1660150
Author(s):  
J. G. ZHENG ◽  
B. C. KHOO
Keyword(s):  
Pressure Wave ◽  
Numerical Study ◽  
Cavitation Model ◽  
Supercavitating Flow ◽  
Through Flow ◽  
Material Erosion ◽  
Pressure Surge ◽  
Noise Vibration ◽  
The Impact ◽  
Compressibility Effects

The unsteady features of supercavitation disturbed by an introduced pressure wave are investigated numerically using a one-fluid cavitation model. The supercavitating flow is assumed to be the homogeneous mixture of liquid and vapour which are locally under both kinetic and thermodynamic equilibrium. The compressibility effects of liquid water are taken into account to model the propagation of pressure wave through flow and its interaction with supercavitation bubble. The interaction between supercavity enveloping an underwater flat-nose cylinder and pressure wave is simulated and the resulting unsteady behavior of supercavitation is illustrated. It is observed that the supercavity will become unstable under the impact of the pressure wave and may collapse locally, which depends on the strength of perturbation. The huge pressure surge accompanying the collapse of supercavitation may cause the material erosion, noise, vibration and efficiency loss of operating underwater devices.

scholarly journals Data Security Storage Method for Power Distribution Internet of Things in Cyber-Physical Energy Systems

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Jiayong Zhong ◽  
Xiaofu Xiong
Keyword(s):  
Internet Of Things ◽  
Data Storage ◽  
Data Security ◽  
Power Distribution ◽  
Homomorphic Encryption ◽  
Control Mode ◽  
Joint Control ◽  
Distributed Data ◽  
Distributed Data Storage ◽  
Storage Method

The existing cloud storage methods cannot meet the delay requirements of intelligent devices in the power distribution Internet of Things (IoT), and it is difficult to ensure the data security in the complex network environment. Therefore, a data Security Storage method for the power distribution IoT is proposed. Firstly, based on the “cloud tube edge end” power distribution IoT structure, a cloud edge collaborative centralized distributed joint control mode is proposed, which makes full use of the collaborative advantages of cloud computing and edge computing to meet the real-time requirements. Then, a distributed data storage method based on the Kademlia algorithm is proposed, and the homomorphic encryption and secret sharing algorithm are used to store the data in the cloud as ciphertext and perform data query directly on the ciphertext. Finally, considering the heterogeneity of edge nodes, the security protection model of edge nodes based on noncooperative differential game is established, and the algorithm of optimal defense strategy of edge nodes is designed to ensure the security of edge nodes. The experimental results show that the proposed method obtained excellent query performance, and the ability to resist network attacks is better than other comparison methods. It can reduce the data storage and query delay and ensure the data security of the system.

Modeling and Simulations of the Supercavitating Vehicle With Its Tail-Slaps

2015 ◽  
Vol 137 (4) ◽  
Author(s):  
Wang Zou ◽  
Hua Liu
Keyword(s):  
Dynamic Equilibrium ◽  
Hydrodynamic Forces ◽  
Rigid Body Dynamics ◽  
Supercavitating Vehicle ◽  
Model Combining ◽  
Motion Modes ◽  
Body Dynamics ◽  
The Stability ◽  
And Control ◽  
Control Surfaces

It is one of the most important stable motion modes to move with tail-slaps for supercavitating vehicle. The periodical tail-slaps provide lift and restoring moment to keep a dynamic equilibrium of the vehicle. Research on the mode is significant to the stability and controllability of supercavity and its vehicle. The effect of the tail-slaps on supercavity is modeled to establish a supercavity model, combining with effects of gravity and angle of attack (AOA). Hydrodynamic forces acting on the vehicle are also formulated in the longitudinal plane based on the supercavity model and rigid body dynamics, considering its tail-slaps and control surfaces. The vehicle, which has a fixed periodical tail-slap, is simulated to calculate its hydrodynamic forces at a constant horizontal speed for different maximum pitch angles using the cavitation number embedded coefficient correction algorithm. The supercavity model is finally verified to some extent by comparing numerical results with experimental ones.

scholarly journals Performance Comparison of Bow and Stern Rudder for High-Speed Supercavitating Vehicles

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Chuang Huang ◽  
Kai Luo ◽  
Kan Qin ◽  
Daijin Li ◽  
Jianjun Dang
Keyword(s):  
High Speed ◽  
Lift Force ◽  
Turbulence Models ◽  
Performance Comparison ◽  
Hydrodynamic Characteristics ◽  
Control Force ◽  
Supercavitating Vehicles ◽  
Wetted Area ◽  
Control Surfaces ◽  
Rudder Angle

To predict the hydrodynamic characteristics and supercavity shape of supercavitation flows, the numerical model including VOF, cavitation model, and turbulence models is presented and validated by a well-established empirical correlation. The numerical method is then employed to simulate the high-speed supercavitating vehicles with two different types of control surfaces: bow rudders and stern rudders. The hydrodynamic characteristics and influences on the supercavity are compared. By contrast with the stern rudder, the bow rudder with the same wetted area is capable of generating a larger control force and moment. Also, the bow rudder introduces a considerable deformation to the forepart of the supercavity, while the stern rudder provides a negligible influence on the supercavity before it. In addition, the bow rudder is fully wetted, and the lift force only changes with the rudder angle. However, the stern rudder is partly wetted; the lift force is not only determined by the rudder angle but also related to the actual wetted status.

scholarly journals Demountable composite steel-concrete floors: A state-of-the-art review

2021 ◽  
Vol 73 (03) ◽  
pp. 249-263
Keyword(s):  
Sustainable Development ◽  
Composite Structures ◽  
Shear Force ◽  
State Of The Art ◽  
Composite Slab ◽  
Research Results ◽  
Shear Connectors ◽  
The Past ◽  
Numerical Research ◽  
Push Out

In keeping with current demands for sustainable development in all segments of the industry, numerous research in the field of steel-concrete composite structures has been focused on developing demountable shear connectors. In the past years, various demountable shear connectors have been suggested, with various mechanisms for transferring shear force between a steel profile and a concrete or composite slab. In this paper, a state of the art on the topic is given, and experimental and numerical research results of push-out and beam tests are summarized.

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