Experimental results for high-speed jitter measurement technique

2005 ◽  
Author(s):  
K. Taylor ◽  
B. Nelson ◽  
A. Chong ◽  
H. Nguyen ◽  
H. Lin ◽  
...  
Keyword(s):  
Measurement Technique ◽  
High Speed ◽  
Experimental Results ◽  
Jitter Measurement

Yaw Galloping of a TLWP Platform Under High Speed Currents by Analytical Methods and its Comparison With Experimental Results

2017 ◽  
Author(s):  
Francisco Lamas ◽  
Miguel A. M. Ramirez ◽  
Antonio Carlos Fernandes
Keyword(s):  
High Speed ◽  
Production Systems ◽  
Experimental Tests ◽  
Experimental Results ◽  
Analytical Methodology ◽  
New Approach ◽  
Laboratory Facilities ◽  
Polynomial Curve ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Analyses

Flow Induced Motions are always an important subject during both design and operational phases of an offshore platform life. These motions could significantly affect the performance of the platform, including its mooring and oil production systems. These kind of analyses are performed using basically two different approaches: experimental tests with reduced models and, more recently, with Computational Fluid Dynamics (CFD) dynamic analysis. The main objective of this work is to present a new approach, based on an analytical methodology using static CFD analyses to estimate the response on yaw motions of a Tension Leg Wellhead Platform on one of the several types of motions that can be classified as flow-induced motions, known as galloping. The first step is to review the equations that govern the yaw motions of an ocean platform when subjected to currents from different angles of attack. The yaw moment coefficients will be obtained using CFD steady-state analysis, on which the yaw moments will be calculated for several angles of attack, placed around the central angle where the analysis is being carried out. Having the force coefficients plotted against the angle values, we can adjust a polynomial curve around each analysis point in order to evaluate the amplitude of the yaw motion using a limit cycle approach. Other properties of the system which are flow-dependent, such as damping and added mass, will also be estimated using CFD. The last part of this work consists in comparing the analytical results with experimental results obtained at the LOC/COPPE-UFRJ laboratory facilities.

The Effect of Strain Rate on the Material Characteristics of Nickel-Based Superalloy Inconel 718

2007 ◽  
Vol 340-341 ◽  
pp. 283-288 ◽  
Author(s):  
Jung Han Song ◽  
Hoon Huh
Keyword(s):  
Dynamic Response ◽  
High Strain Rate ◽  
Strain Rate ◽  
Turbine Blade ◽  
Inconel 718 ◽  
High Speed ◽  
High Strain ◽  
Split Hopkinson Pressure Bar ◽  
Experimental Results ◽  
Stress Wave Propagation

The dynamic response of the turbine blade materials is indispensable for analysis of erosions of turbine blades as a result of impulsive loading associated with gas flow. This paper is concerned with the dynamic material properties of the Inconel 718 alloy which is widely used in the high speed turbine blade. The dynamic response at the corresponding level of the strain rate should be acquired with an adequate experimental technique and apparatus due to the inertia effect and the stress wave propagation. In this paper, the dynamic response of the Inconel 718 at the intermediate strain rate ranged from 1/s to 400/s is obtained from the high speed tensile test and that at the high strain rate above 1000/s is obtained from the split Hopkinson pressure bar test. The effects of the strain rate on the dynamic flow stress, the strain rate sensitivity and the failure elongation are evaluated with the experimental results. Experimental results from both the quasi-static and the high strain rate up to 3000/s are interpolated in order to construct the constitutive relation that should be applied to simulate the dynamic behavior of the turbine blade made of the Inconel 718.

Experimental Study of Turbulent Macroinstabilities in an Agitated System with Axial High-Speed Impeller and with Radial Baffles

1996 ◽  
Vol 61 (6) ◽  
pp. 856-867 ◽  
Author(s):  
Oldřich Brůha ◽  
Ivan Fořt ◽  
Pavel Smolka ◽  
Milan Jahoda
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
High Speed ◽  
Experimental Results ◽  
Turbulent Regime ◽  
Frequency Of Occurrence ◽  
Visualization Method ◽  
Entire Flow

The frequency of turbulent macroinstability occurrence was measured in liquids agitated in a cylindrical baffled vessel. As it has been proved by preceding experimental results of the authors, the stochastic quantity with frequency of occurrence of 10-1 to 100 s-1 is concerned. By suitable choosing the viscosity of liquids and frequency of impeller revolutins, the region of Reynolds mixing numbers was covered from the pure laminar up to fully developed turbulent regime. In addition to the equipment making it possible to record automatically the macroinstability occurrence, also the visualization method and videorecording were employed. It enabled us to describe in more detail the form of entire flow field in the agitated system and its behaviour in connection with the macroinstability occurrence. It follows from the experiments made that under turbulent regime of flow of agitated liquids the frequency of turbulent macroinstability occurrence is the same as the frequency of the primary circulation of agitated liquid.

A Wavelength Interleaved DWDM ROF System with 60GHz Optical OFDM Signal

2011 ◽  
Vol 130-134 ◽  
pp. 2245-2248
Author(s):  
Yong Hong Ma ◽  
Chong Xiang Zhang ◽  
Pan Zhang
Keyword(s):  
High Speed ◽  
Radio Over Fiber ◽  
Experimental Results ◽  
Arrayed Waveguide Grating ◽  
Waveguide Grating ◽  
Access System ◽  
Ofdm Signal ◽  
The Future ◽  
Optical Ofdm ◽  
Arrayed Waveguide

we demonstrate a wavelength interleaved DWDM Radio-over-Fiber (ROF) system for providing 1-Gb/s OFDM signal in downlink and 1-Gb/s OOK data in uplink simultaneously. In this scheme, we use only one arrayed waveguide grating device at the remote node to realize both the de-multiplexing and multiplexing functions. The experimental results demonstrate that this scheme is feasible to the future broadband high-speed OFDM-ROF access system.

Ripple Technique; a Novel Non-Contact Wafer Emissivity and Temperature Method for RTP

1991 ◽  
Vol 224 ◽  
Author(s):  
C. Schietinger ◽  
B. Adams ◽  
C. Yarling
Keyword(s):  
Optical Fiber ◽  
Measurement Technique ◽  
Thermal Processing ◽  
High Speed ◽  
Rapid Thermal Processing ◽  
Wafer Surface ◽  
Speed Measurement ◽  
Temperature Method ◽  
Emissivity Measurement ◽  
Emissivity Measurements

AbstractA novel wafer temperature and emissivity measurement technique for rapid thermal processing (RTP) is presented. The ‘Ripple Technique’ takes advantage of heating lamp AC ripple as the signature of the reflected component of the radiation from the wafer surface. This application of Optical Fiber Thermometry (OFT) allows high speed measurement of wafer surface temperatures and emissivities. This ‘Ripple Technique’ is discussed in theoretical and practical terms with wafer data presented. Results of both temperature and emissivity measurements are presented for RTP conditions with bare silicon wafers and filmed wafers.

A Compound Vibratory Mode in High Speed Vibratory Tapping

2009 ◽  
Vol 69-70 ◽  
pp. 379-383 ◽  
Author(s):  
L. Wang ◽  
Gui Cheng Wang ◽  
J.H. Zhu ◽  
Hong Jie Pei ◽  
L.F. Lin
Keyword(s):  
Stainless Steel ◽  
High Speed ◽  
Experimental Results

Based on the investigation of two traditional vibratory modes, this paper puts forward a novel vibratory mode in high speed tapping. Vibratory tapping on stainless steel with all kinds of vibratory modes is carefully studied. Experimental results show that the new vibratory mode not only preserves the machining effect of the separable vibratory tapping, but also increases the life of tap. Therefore this study provides a new solution to increase the performance of high speed vibrat- ion tapping.

Rotordynamics Performance of Hybrid Foil Bearing Under Forced Vibration Input

2017 ◽  
Author(s):  
Daejong Kim ◽  
Brian Nicholson ◽  
Lewis Rosado ◽  
Garry Givan
Keyword(s):  
Impulse Response ◽  
High Speed ◽  
Load Capacity ◽  
Supply System ◽  
Forced Response ◽  
Experimental Results ◽  
Lateral Acceleration ◽  
Foil Bearings ◽  
Foil Bearing ◽  
Gas Supply

Foil bearings are one type of hydrodynamic air/gas bearings but with a compliant bearing surface supported by structural material that provides stiffness and damping to the bearing. The hybrid foil bearing (HFB) in this paper is a combination of a traditional hydrodynamic foil bearing with externally-pressurized air/gas supply system to enhance load capacity during the start and to improve thermal stability of the bearing. The HFB is more suitable for relatively large and heavy rotors where rotor weight is comparable to the load capacity of the bearing at full speed and extra air/gas supply system is not a major added cost. With 4,448N∼22,240N thrust class turbine aircraft engines in mind, the test rotor is supported by HFB in one end and duplex rolling element bearings in the other end. This paper presents experimental work on HFB with diameter of 102mm performed at the US Air force Research Laboratory. Experimental works include: measurement of impulse response of the bearing to the external load corresponding to rotor’s lateral acceleration of 5.55g, forced response to external subsynchronous excitation, and high speed imbalance response. A non-linear rotordynamic simulation model was also applied to predict the impulse response and forced subsynchronous response. The simulation results agree well with experimental results. Based on the experimental results and subsequent simulations, an improved HFB design is also suggested for higher impulse load capability up to 10g and rotordynamics stability up to 30,000rpm under subsynchronous excitation.

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