This paper presents the dynamic performance characteristics of a hydraulic vortex rate gyro using aviation oil and the design guide considering both the static sensitivity and the dynamic characteristics. The dynamic characteristics of the hydraulic vortex rate gyro consist of the time lag when the signal flow arrives at the probe tube and of the time delay when it takes to produce the stable vortex flow in the vortex chamber. The time delay was analyzed by estimating that the tangential velocity of the fluid entering into the vortex chamber was reduced by the inertia force of fluid which had been located in the chamber, and it was expressed with the first order delay system. The experiment was conducted by varing the factors affecting the dynamic characteristicsvortex chamber dimensions, angular velocity etc. -and the output responses of H.V.R. gyro to the step input of angular velocity were measured. And then, the empirical formula of the coefficient of the time constant was obtained by analyzing the step responses of hydraulic vortex rate gyro, and it was confirmed that the experimental time lags agreed very well with theoretical ones reflecting displacement thickness in the chamber.
Transient response of short rectangular lines with a low pressure bubble at the end of the line is discussed in this study. And it is related with the switching mechanism in the wall-attachment fluid amplifier. For the stepwise input signal, the attenuation of the output signal becomes remarkable as the nozzle-exit velocity increases. The pressure change in the low pressure bubble with switching differs from that of no switching. And it is affected by the size of the low pressure bubble and the pressure level of the input signal. For the pulsatile input signal, the pressure in the bubble may be influenced by the interaction between the input signal and the jet at the end of the line. And calculated results by the method of characteristics show considerably good agreement with experimental ones.
The use of RAYLEIGH and vibrational RAMAN spectroscopic techniques in flame temperature measurements is examined. The experimental apparatus consisted of an Argon-ion laser (1.2 W at 488nm), a double monochromator, a recording system (photon-counter or data recorder), and a pair of multi-pass reflectors, which were used when high scattering light intensity was required. In an experiment using the RAMAN spectroscopy, an H2 diffusion flame has been in- vestigated. The results of N2 and O2 vibrational temperature measurements are presented, and the temperature profiles for N2 are further examined in comparison with the profiles determined through thermocouple measurements. CH4-air premixed flames have been studied for the assessment of RAYLEIGH scattering spectroscopy. Time-averaged temperature profiles of a laminar flame obtained by this technique are compared with the results of thermocouple measurements. RAYLEIGH thermometry has also been applied to a turbulent flame, demonstrating that this technique provides reliable temperature determination with sufficient time resolution.
Probabilistic properties of nonlinear response of shallow spherical shells with clamped edges to random excitation are analytically investigated with the aid of simulation method in order to disclose the effects of the curvature on the acoustic fatigue lives. The deflection is expressed as a series expansion of the axisymmetric normal modes of vibration, and the nonlinear equations of vibration for the generalized coordinates are derived. The equations in the three modes approximation are numerically solved by NEW-MARK'S β method for random excitation forces. The probabilistic quantities of the response are calculated for various combinations of the pressure level and the curvature. The results have revealed the following properties. At high pressure levels the large amplitude vibration includes the snap-through buckling. The change of vibrational mode occurs during the snap-through. At very high pressure levels the probabilistic properties of the center deflection approach those of the flat panel. The fatigue lives of the shells can be shorter than those of the flat plate when the vibration includes the snap-through. The fatigue properties cannot be explained by the mean value and the standard deviation of the stress but explained by its probability density function (PDF), because the PDF is quite different from the Gaussian distribution. Then the static equilibrium load-deflection curves are calculated from the same discretized nonlinear equations and show good agreement with the previous results.
Two Comments are given conceming yawing controls due to aileron at high angle of attack. Firstly, the lateral control departure parameter (LCDP) can be interpreted as a zero of the transfer function of aileron-to-yaw control. Secondly, the use of aileron is most effective for yaw control at extremely high angle of attack: numerical calculations are given for the recovery from flat-spin.