Torsional Flutter in Stalled Cascade

1978 ◽  
Vol 100 (2) ◽  
pp. 317-325 ◽  
Author(s):  
S. Yashima ◽  
H. Tanaka
Keyword(s):  
Theoretical Study ◽  
Experimental Results ◽  
Water Tunnel ◽  
Computational Results ◽  
Linear Cascade ◽  
Singularity Method ◽  
Reduced Frequency ◽  
Aerodynamic Moment ◽  
Good Agreement

Applying free streamline theory and singularity method, a theoretical study is developed for the torsional flutter problem in fully stalled cascade. Aerodynamic moment acting on a vibrating blade is calculated for some cascade conditions. Computational results show that critical reduced frequency is much higher in the case of stalled cascade than unstalled cascade and affected by the position of pitching center. Experiments were carried out using a water tunnel with a linear cascade, and the unsteady moment acting on the vibrating blade was measured. Computational and experimental results show fairly good agreement.

scholarly journals Torsional Flutter in Stalled Cascade

1977 ◽  
Author(s):  
S. Yashima ◽  
H. Tanaka
Keyword(s):  
Theoretical Study ◽  
Experimental Results ◽  
Water Tunnel ◽  
Computational Results ◽  
Linear Cascade ◽  
Singularity Method ◽  
Reduced Frequency ◽  
Aerodynamic Moment ◽  
Good Agreement

Applying free streamline theory and singularity method, a theoretical study is developed for the torsional flutter problem in fully stalled cascade. Aerodynamic moment acting on a vibrating blade is calculated for some cascade conditions. Computational results show that critical reduced frequency is much higher in the case of stalled cascade than unstalled one and affected by the position of pitching center. Experiments were carried out using a water tunnel with a linear cascade, and the unsteady moment acting on the vibrating blade was measured. Computational and experimental results show fairly good agreement.

Paper 31: Capsule-Pipeline Flow—A Theoretical Study

1969 ◽  
Vol 184 (7) ◽  
pp. 89-100
Author(s):  
V. K. Garg ◽  
G. F. Round
Keyword(s):  
Theoretical Study ◽  
Theoretical Solution ◽  
Experimental Results ◽  
Free Flow ◽  
Average Flow ◽  
Pipe System ◽  
Liquid Carrier ◽  
Pipeline Flow ◽  
Theoretical Predictions ◽  
Good Agreement

Theoretical predictions of the behaviour of various parameters governing the free flow of a single, very long, denser-than-liquid carrier, cylindrical capsule in a horizontal pipeline are reported in this paper. The study was carried out for average flow velocities of approximately 1–10 ft/s in pipes of diameters 4, 6, 12, and 24 in with diameter ratios varying from 0·9 to 0·99. While two liquid carriers—water and an oil ( μ = 10 cP and sp. gr. = 0·85)—were used, the eccentricity of the capsule-pipe system was fixed at 0·999. The theoretical solution was found to be in good agreement with the experimental results.

Theoretical study of the rovibrational spectrum of He2–OCS

2010 ◽  
Vol 88 (8) ◽  
pp. 779-786 ◽  
Author(s):  
Xiao-Gang Wang ◽  
Tucker Carrington,
Keyword(s):  
Dipole Moment ◽  
Large Amplitude ◽  
Theoretical Study ◽  
Van Der Waals ◽  
Potential Functions ◽  
Experimental Results ◽  
Basis Sets ◽  
Van Der Waals Complex ◽  
Good Agreement

We report calculated microwave and infrared rovibrational transitions of the van der Waals complex He2–OCS. The calculations were done using a product basis, a Lanczos eigensolver, and potentials built from He–OCS, and He–He potential functions taken from the literature. All five of the large amplitude coordinates are treated exactly and calculations are done for J values up to five. All rovibrational levels are converged to 0.001 cm–1 by using basis sets with as many as 87 million funcions. Good agreement is found with previously reported experimental results. Although we assume that the dipole moment is along the OCS axis, we find transitions with appreciable intensity between different torsion states.

Theoretical Study on the Flow About Savonius Rotor

1984 ◽  
Vol 106 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Takenori Ogawa
Keyword(s):  
Dimensional Analysis ◽  
Theoretical Study ◽  
Separated Flow ◽  
Vortex Method ◽  
Experimental Results ◽  
Two Dimensional ◽  
Discrete Vortex ◽  
Discrete Vortex Method ◽  
Savonius Rotor ◽  
Singularity Method

A method for the two-dimensional analysis of the separated flow about Savonius rotors is presented. Calculations are performed by combining the singularity method and the discrete vortex method. The method is applied to the simulation of flows about a stationary rotor and a rotating rotor. Moreover, torque and power coefficients are computed and compared with the experimental results presented by Sheldahl et al. Theoretical and experimental results agree well qualitatively.

Inducing Frictional Force to Enhance the Transient Response in Beams

2019 ◽  
Vol 22 (2) ◽  
pp. 88-93
Author(s):  
Hamed Khanger Mina ◽  
Waleed K. Al-Ashtrai
Keyword(s):  
Numerical Analysis ◽  
Transient Response ◽  
Frictional Force ◽  
Damping Ratio ◽  
Experimental Results ◽  
Damping Capacity ◽  
Tightening Force ◽  
Contact Areas ◽  
Good Agreement ◽  
Ansys Workbench

This paper studies the effect of contact areas on the transient response of mechanical structures. Precisely, it investigates replacing the ordinary beam of a structure by two beams of half the thickness, which are joined by bolts. The response of these beams is controlled by adjusting the tightening of the connecting bolts and hence changing the magnitude of the induced frictional force between the two beams which affect the beams damping capacity. A cantilever of two beams joined together by bolts has been investigated numerically and experimentally. The numerical analysis was performed using ANSYS-Workbench version 17.2. A good agreement between the numerical and experimental results has been obtained. In general, results showed that the two beams vibrate independently when the bolts were loosed and the structure stiffness is about 20 N/m and the damping ratio is about 0.008. With increasing the bolts tightening, the stiffness and the damping ratio of the structure were also increased till they reach their maximum values when the tightening force equals to 8330 N, where the structure now has stiffness equals to 88 N/m and the damping ratio is about 0.062. Beyond this force value, increasing the bolts tightening has no effect on stiffness of the structure while the damping ratio is decreased until it returned to 0.008 when the bolts tightening becomes immense and the beams behave as one beam of double thickness.

PHOTOINDUCED NONLINEAR OCTUPOLAR POLARIZATION: TRANSIENT AND PERMANENT REGIMES

1996 ◽  
Vol 05 (04) ◽  
pp. 653-670 ◽  
Author(s):  
CÉLINE FIORINI ◽  
JEAN-MICHEL NUNZI ◽  
FABRICE CHARRA ◽  
IFOR D.W. SAMUEL ◽  
JOSEPH ZYSS
Keyword(s):  
Theoretical Analysis ◽  
Second Harmonic ◽  
Experimental Results ◽  
Polar Field ◽  
Rotational Spectrum ◽  
Dual Frequency ◽  
One Dimensional ◽  
Ethyl Violet ◽  
Disperse Red 1 ◽  
Good Agreement

An original poling method using purely optical means and based on a dual-frequency interference process is presented. We show that the coherent superposition of two beams at fundamental and second-harmonic frequencies results in a polar field with an irreducible rotational spectrum containing both a vector and an octupolar component. This enables the method to be applied even to molecules without a permanent dipole such as octupolar molecules. After a theoretical analysis of the process, we describe different experiments aiming at light-induced noncentrosymmetry performed respectively on one-dimensional Disperse Red 1 and octupolar Ethyl Violet molecules. Macroscopic octupolar patterning of the induced order is demonstrated in both transient and permanent regimes. Experimental results show good agreement with theory.

scholarly journals Comparison of Experimental and Numerical Transient Drop Deformation during Transition through Orifices in High-Pressure Homogenizers

2021 ◽  
Vol 5 (3) ◽  
pp. 32
Author(s):  
Benedikt Mutsch ◽  
Peter Walzel ◽  
Christian J. Kähler
Keyword(s):  
High Pressure ◽  
Visual Analysis ◽  
Imaging Technique ◽  
Extensional Flow ◽  
Droplet Breakup ◽  
Experimental Results ◽  
Drop Deformation ◽  
Droplet Deformation ◽  
Shadow Imaging ◽  
Good Agreement

The droplet deformation in dispersing units of high-pressure homogenizers (HPH) is examined experimentally and numerically. Due to the small size of common homogenizer nozzles, the visual analysis of the transient droplet generation is usually not possible. Therefore, a scaled setup was used. The droplet deformation was determined quantitatively by using a shadow imaging technique. It is shown that the influence of transient stresses on the droplets caused by laminar extensional flow upstream the orifice is highly relevant for the droplet breakup behind the nozzle. Classical approaches based on an equilibrium assumption on the other side are not adequate to explain the observed droplet distributions. Based on the experimental results, a relationship from the literature with numerical simulations adopting different models are used to determine the transient droplet deformation during transition through orifices. It is shown that numerical and experimental results are in fairly good agreement at limited settings. It can be concluded that a scaled apparatus is well suited to estimate the transient droplet formation up to the outlet of the orifice.

Simulation of Sphere’s Motion Induced by Shock Waves

2012 ◽  
Vol 134 (10) ◽  
Author(s):  
Dan Igra ◽  
Ozer Igra ◽  
Lazhar Houas ◽  
Georges Jourdan
Keyword(s):  
Shock Waves ◽  
Drag Coefficient ◽  
Drag Force ◽  
Stationary Flow ◽  
Experimental Results ◽  
Experimental Findings ◽  
Sphere Drag ◽  
Simulation Scheme ◽  
Good Agreement

Simulations of experimental results appearing in Jourdan et al. (2007, “Drag Coefficient of a Sphere in a Non-Stationary Flow: New Results,”Proc. R. Soc. London, Ser. A, 463, pp. 3323–3345) regarding acceleration of a sphere by the postshock flow were conducted in order to find the contribution of the various parameters affecting the sphere drag force. Based on the good agreement found between present simulations and experimental findings, it is concluded that the proposed simulation scheme could safely be used for evaluating the sphere’s motion in the postshock flow.

Explanation of the Influence of Inflow Air Content on the Lift of Cavitating Hydrofoils

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Eduard Amromin
Keyword(s):  
Experimental Data ◽  
Theoretical Study ◽  
Lift Coefficient ◽  
Cavity Surface ◽  
Air Bubbles ◽  
Incoming Flow ◽  
Fluid Density ◽  
Air Content ◽  
Theoretical Results ◽  
Good Agreement

According to several known experiments, an increase of the incoming flow air content can increase the hydrofoil lift coefficient. The presented theoretical study shows that such increase is associated with the decrease of the fluid density at the cavity surface. This decrease is caused by entrainment of air bubbles to the cavity from the surrounding flow. The theoretical results based on such explanation are in a good agreement with the earlier published experimental data for NACA0015.

Nuclear magnetic resonance microscopy with 4-μm resolution: Theoretical study and experimental results

1988 ◽  
Vol 15 (6) ◽  
pp. 815-824 ◽  
Author(s):  
Z. H. Cho ◽  
C. B. Ahn ◽  
S. C. Juh ◽  
H. K. Lee ◽  
R. E. Jacobs ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Theoretical Study ◽  
Experimental Results ◽  
Magnetic Resonance Microscopy ◽  
Nuclear Magnetic
Sign in / Sign up

Export Citation Format

Share Document