Fast flow control in high-speed communications networks

2002 ◽  
Author(s):  
C. Kwan ◽  
R. Xu ◽  
L. Haynes ◽  
Chih-Hsien Chou ◽  
E. Geraniotis
Keyword(s):  
Flow Control ◽  
High Speed ◽  
Communications Networks ◽  
Fast Flow

scholarly journals A Critical Review of Supersonic Flow Control for High-Speed Applications

2021 ◽  
Vol 11 (15) ◽  
pp. 6899
Author(s):  
Abdul Aabid ◽  
Sher Afghan Khan ◽  
Muneer Baig
Keyword(s):  
Supersonic Flow ◽  
Flow Control ◽  
Active Control ◽  
Critical Review ◽  
High Speed ◽  
Passive Control ◽  
Control Method ◽  
Sudden Expansion ◽  
Control Approach ◽  
Cost Efficient

In high-speed fluid dynamics, base pressure controls find many engineering applications, such as in the automobile and defense industries. Several studies have been reported on flow control with sudden expansion duct. Passive control was found to be more beneficial in the last four decades and is used in devices such as cavities, ribs, aerospikes, etc., but these need additional control mechanics and objects to control the flow. Therefore, in the last two decades, the active control method has been used via a microjet controller at the base region of the suddenly expanded duct of the convergent–divergent (CD) nozzle to control the flow, which was found to be a cost-efficient and energy-saving method. Hence, in this paper, a systemic literature review is conducted to investigate the research gap by reviewing the exhaustive work on the active control of high-speed aerodynamic flows from the nozzle as the major focus. Additionally, a basic idea about the nozzle and its configuration is discussed, and the passive control method for the control of flow, jet and noise are represented in order to investigate the existing contributions in supersonic speed applications. A critical review of the last two decades considering the challenges and limitations in this field is expressed. As a contribution, some major and minor gaps are introduced, and we plot the research trends in this field. As a result, this review can serve as guidance and an opportunity for scholars who want to use an active control approach via microjets for supersonic flow problems.

scholarly journals FOSquare: A Novel Optical HPC Interconnect Network Architecture Based on Fast Optical Switches with Distributed Optical Flow Control

Photonics ◽  
2021 ◽  
Vol 8 (1) ◽  
pp. 11
Author(s):  
Fulong Yan ◽  
Changshun Yuan ◽  
Chao Li ◽  
Xiong Deng
Keyword(s):  
Flow Control ◽  
Network Architecture ◽  
Network Performance ◽  
Optical Switches ◽  
Low Power Consumption ◽  
Low Latency ◽  
High Bandwidth ◽  
Fast Flow ◽  
Real Traffic ◽  
Interconnect Network

Interconnecting networks adopting Fast Optical Switches (FOS) can achieve high bandwidth, low latency, and low power consumption. We propose and demonstrate a novel interconnecting topology based on FOS (FOSquare) with distributed fast flow control which is suitable for HPC infrastructures. We also present an Optimized Mapping (OPM) algorithm that maps the most communication-related processes inside a rack. We numerically investigate and compare the network performance of FOSquare with Leaf-Spine under real traffic traces collected by running multiple applications (CG, MG, MILC, and MINI_MD) in an HPC infrastructure. The numerical results show that the FOSquare can reduce >10% latency with respect to Leaf-Spine under the scenario of 16 available cores.

scholarly journals Plasma Synthetic Jet Actuators for Active Flow Control

Actuators ◽  
2018 ◽  
Vol 7 (4) ◽  
pp. 77 ◽  
Author(s):  
Haohua Zong ◽  
Matteo Chiatto ◽  
Marios Kotsonis ◽  
Luigi de Luca
Keyword(s):  
Flow Control ◽  
High Speed ◽  
High Reynolds Number ◽  
Mechanical Efficiency ◽  
Synthetic Jet ◽  
High Speed Flow ◽  
Speed Flow ◽  
Jet Actuators ◽  
Characterization Studies ◽  
High Reynolds

The plasma synthetic jet actuator (PSJA), also named as sparkjet actuator, is a special type of zero-net mass flux actuator, driven thermodynamically by pulsed arc/spark discharge. Compared to widely investigated mechanical synthetic jet actuators driven by vibrating diaphragms or oscillating pistons, PSJAs exhibit the unique capability of producing high-velocity (>300 m/s) pulsed jets at high frequency (>5 kHz), thus tailored for high-Reynolds-number high-speed flow control in aerospace engineering. This paper reviews the development of PSJA in the last 15 years, covering the major achievements in the actuator working physics (i.e., characterization in quiescent air) as well as flow control applications (i.e., interaction with external crossflow). Based on the extensive non-dimensional laws obtained in characterization studies, it becomes feasible to design an actuator under several performance constraints, based on first-principles. The peak jet velocity produced by this type of actuator scales approximately with the cubic root of the non-dimensional energy deposition, and the scaling factor is determined by the electro-mechanical efficiency of the actuator (O(0.1%–1%)). To boost the electro-mechanical efficiency, the energy losses in the gas heating phase and thermodynamic cycle process should be minimized by careful design of the discharge circuitry as well as the actuator geometry. Moreover, the limit working frequency of the actuator is set by the Helmholtz natural resonance frequency of the actuator cavity, which can be tuned by the cavity volume, exit orifice area and exit nozzle length. In contrast to the fruitful characterization studies, the application studies of PSJAs have progressed relatively slower, not only due to the inherent difficulties of performing advanced numerical simulations/measurements in high-Reynolds-number high-speed flow, but also related to the complexity of designing a reliable discharge circuit that can feed multiple actuators at high repetition rate. Notwithstanding these limitations, results from existing investigations are already sufficient to demonstrate the authority of plasma synthetic jets in shock wave boundary layer interaction control, jet noise mitigation and airfoil trailing-edge flow separation.

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