Triangular Jets Research Articles

P4381Improvement of the PISA method in the setting of mitral regurgitation of complex geometry

Abstract Background Doppler echocardiographic methods, such as proximal isovelocity surface area (PISA) are used to quantify mitral regurgitations. However, their accuracy and reproducibility are still discussed, especially in case of mitral regurgitations of complex geometry. Purpose The aim of this study was to test in-vitro the accuracy of the PISA method depending on the shape and number of regurgitant flows. Methods Several regurgitant volumes (RV) were produced through various regurgitation severities and shapes in a left heart double activation simulator. Circular mitral regurgitation (MR) was performed with a circular orifice in a rigid plate. Triangular and oblong MR were performed by suturing the extremity of a bioprosthesis leaflet to the annulus. Multiple jets regurgitation was performed by suturing centrally the two leaflets of an anatomically shaped mitral valve made of hydrogel. A transesophageal echocardiography probe was used to acquire the data. The RV was calculated with the classical PISA method (hemispheric assumption), or by considering the PISA as a hemicylinder or a double hemisphere. It was then compared to a reference value obtained from an electromagnetic flowmeter measurement (accuracy ± 2 ml/min). Results A central and circular orifice was correctly quantified, as expected, with the hemispheric assumption (bias 0.2±1.9 ml, p=0.46). For a triangular central jet, the hemispheric assumption best estimated the RV (−3.5±14.8 ml, p=0.10). An oblong MR was underestimated with the hemispheric assumption (−18.3±14.9 ml, p<0.01) whereas the hemicylindrical assumption was more accurate (−0.2±5.8 ml, p=0.85). In case of 2 regurgitant jets, considering only the largest jet led to an important underestimation (−10.9±5.6 ml, p<0.01), whereas adding the two RV was more accurate (−1.2±8.2 ml, p=0.50). Conclusions In case of a single central orifice, the hemispheric assumption correctly quantified the MR. In case of an oblong orifice, the hemicylindrical assumption provided a good quantification with simple measurements. In case of multiple jets of different sizes, it was more accurate to consider both jets for RV calculation. Acknowledgement/Funding Képhalios part of Affluent Medical

Experimental Studies on Decay and Spread Characteristics of an Overexpanded Triangular Supersonic Jet

Experiments were conducted on overexpanded equilateral triangular supersonic jets (Mach 1.8) at Reynolds numbers 6.71 × 105 and 4.81 × 105 to study their decay and spread characteristics by means of measuring the jet centreline and lateral total pressure distributions. Schlieren images of the jets were also taken to study the shock patterns in the jet structure. The above Reynolds numbers correspond to the nozzle inlet total pressures of 550 kPa (6.71 × 105) and 360 kPa (4.81 × 105). For comparison purposes the above experiments were repeated on a circular nozzle with the same exit area and area ratio (1.44) and total pressures. The observations from the experiments reveal that the triangular jet exhibits a shorter supersonic core compared with the circular jet, i.e., reduction of 34.25% at 360 kPa and 31.11% at 550 kPa. The total pressure decay is more abrupt and a greater loss of the total pressure occurs closer to the nozzle exit plane in the case of the triangular jet compared to the circular jet. The lateral total pressure distribution reveals that the jet spreading rate is greater on the flat than on the corner side of the triangular jet.

Shock structures of underexpanded non-circular slot jets

Flow visualization studies using shadowgraph technique are carried out to investigate the shock evolution from non-circular slot jets at various under-expansion levels. The non-circular topologies considered are triangular, square and elliptic, and the circular jet is taken as the baseline case for the study. These jets are underexpanded in the pressure ratio (R) range of 2–6 corresponding to a fully expanded jet Mach number up to 1.85. Results indicate that the shock cell structures of non-circular jets strongly depend upon the initial shape of the topology. The shock structures of triangular jet have additional secondary oblique shocks that are distinct from those of other non-circular jets. Mach disk is almost absent in a shock cell structure of triangular jet, which is unlike the case of other jets used in the study. The study suggests that square jet undergoes faster diffusion process compared with the triangular jet. Axis-switching phenomenon is predicted for the elliptical jet at a distance of 3–7 equivalent diameters.

Hydraulic Performance and Jet Breakup Characteristics of the Impact Sprinkler with Circular and Non-circular Nozzles

HighlightsThe hydraulic performance of the impact sprinkler with circular and non-circular nozzles were measured.A High-Speed Photography (HSP) technique was employed to extract the jet breakup process of the impact sprinkler.Two index equations of jet characteristic lengths and equivalent diameters of non-circular nozzles were fitted. Abstract. An experiment was carried out to investigate the hydraulic performance of an impact sprinkler by using circular and non-circular nozzles. A High-Speed Photography (HSP) technique was employed to extract the breakup process and flow behavior of low-intermediate pressure water jets issued from the different types of orifices. These orifices were selected by the principle of equal flowrate with the same pressure. Moreover, two characteristic lengths: the jet breakup length and the initial amplitude of surface wave were measured. It was found that the sprinkler with circular nozzles produced the largest radius of throw followed by square nozzles and regular triangular nozzles when the cone angle of nozzle and pressure were unchanged, while the sprinkler with regular triangular nozzle had the best variation trend of water distribution and combination uniformity coefficient. Regular triangular jets exhibited a higher degree in breakup and the shortest breakup length compared with the square jets and the circular jets. The initial amplitudes of surface waves of regular triangular jets were larger than the square jets and the circular jets with the same cone angle. Two index equations of jet characteristic lengths and equivalent diameters of both circular and non-circular orifices were fitted with a relative error of less than 10%, which means the fitting formulas were accurate. Keywords: Breakup length, Fitting formula, Hydraulic performance, Initial amplitude, Non-circular jets.

Experimental Study on Jet Breakup Morphologies and Jet Characteristic Parameters of Non-circular Nozzles under Low-intermediate Pressures

Abstract. A High-Speed Photography (HSP) technique was used to investigate the breakup process and flow behavior of low-intermediate pressure water jets issued from square and triangular shaped nozzles. The non-circular orifices were designed based on the principle of equal flowrate with the same pressure in relation to the circular orifice. The breakup morphologies and boundary structures of the jets were studied under different nozzles and working pressures. Two forms of droplet formation and the process of droplet formation, in addition to the jet breakup lengths, initial amplitudes of surface waves and jet diffusion angles of different nozzles were evaluated. It was found that the jet presented a good continuity and fluidity in the initial section, and the fluid bands gradually appeared due to the air resistance and the jet break up as the disturbance intensifies. The degree of jet breakup was enhanced with the increase of pressure and cone nozzle angle. The random appearance of the fluid band structures and the dactylitic textures near the nozzles for non-circular jets appeared earlier than those produced by the circular jets. The small satellite droplets with different shapes and sizes were seen inside and outside the jet interface. Triangular jets exhibited the shortest breakup length, the initial amplitude of surface wave, and the diffusion angle of the jet at the same pressure were largest compared with square and circular jets. Two index equations of jet characteristic lengths and equivalent diameters of both circular and non-circular nozzles were fitted with a relative error of less than 10%, which means the fitting formulas are accurate. Keywords: Breakup length, High-speed photography, MATLAB simulation, Non-circular nozzle, Surface wave amplitude.

Impinging jet noise reduction using non-circular jets

Experimental studies in the acoustic far field and flow visualization are carried out on circular and non-circular impinging jets at a nozzle to plate distance ratio of 5, for the nozzle pressure ratios of 1.8, 4, and 6. Spectra and directivity of the overall sound pressure level of circular jets are compared with those of non-circular jets for the same nozzle pressure ratios, at various emission angles. Non-circular jets mitigate the transonic impinging tones at around the critical pressure ratio, compared to the circular jet. Square jet is quieter at low nozzle pressure ratios by 5–8 dB compared to the circular jet. At higher under expansion conditions, the triangular and square jets almost completely eliminate the supersonic impinging tones. Elliptical jet is noisy at a nozzle pressure ratio of 6, even compared to the circular jet. Elliptical minor axis plane is quieter at lower nozzle pressure ratios compared to the major axis plane and the trend is reversed for the higher nozzle pressure ratios. Schlieren flow visualization studies reveal that the shock cell structures are weakened and symmetry of the shock cells are lost for the non-circular jets compared to the circular jet.

On the Development of Incompressible Round and Equilateral Triangular Jets Due to Reynolds Number Variation

The aim of this study is to examine the effects of Reynolds number (Re = 6000–20,000) on mean and turbulent quantities as well as turbulent structures in the near and intermediate regions of equilateral triangular and round sharp contraction jets. The results show shorter potential core length, faster growth of turbulence intensity, and faster diffusion of turbulent structures to the centerline of the triangular jets, implying enhanced mixing in the near field of these jets. On the other hand, the velocity decay and jet spread rates are higher in the round jets. The obtained data in the round jets show that the jet at Re = 6000 has the most effective mixing, while an increase in Reynolds number reduces the mixing performance. In the triangular jets, however, no Reynolds number effects were observed on the measured quantities including the length of the potential core, the decay and spread rates, the axis-switching locations, and the value of the Reynolds number. In addition, the asymptotic values of the relative turbulence intensities on the jet centerline are almost independent of the Reynolds number and geometry. The ratios of transverse and spanwise Reynolds stresses are unity except close to the jet exit where the flow pattern in the major plane of the triangular jet deflects toward the flat side. Proper orthogonal decomposition (POD) analysis revealed that turbulent structures in minor and major planes have identical fractional kinetic energy. The integral length scales increased linearly with the streamwise distance with identical slope for all the test cases.

Numerical investigation of heat transfer characteristics of impinging synthetic jets with different waveforms

Synthetic jet, potentially useful in electronic cooling, is numerically studied considering various waveforms for the purpose of heat transfer enhancement and compare to the corresponding steady air jet. In the present study, sinusoidal, rectangular and triangular synthetic jets are applied to a confined two-dimensional slot jet impinging on a heated plate adopting SST/k-ω turbulence model. The jet frequency is varied from 10 to 400 Hz for Reynolds numbers (Re) in the range of 1553–7766 (Strouhal number 0.012 ≤ St ≤ 2.4) and jet-to-surface distances ranging from 2 to 8. Generally, the cooling performance is enhanced by increase in Re and with the increase in frequency and H/W, the cooling performance shows a first increase and then decrease trend. Results of simulation indicate that conditions at the turning frequency correspond to critical St = 0.24–0.48 have higher heat transfer rate than other cases at the same Re. When St < 0.06, the heat transfer performance of rectangular jets can be better than the other two jets. When St is close to the critical St, the comparison of heat transfer enhancement is that triangular jets > sinusoidal jets > rectangular jets. Time sequence of streamline and velocity contour image is presented to further explain this phenomenon. Moreover, most conditions show good heat transfer enhancement compare to the corresponding steady jet except conditions in which St is too high (St > 1.2) or H/W is too low, or H/W is too large (H/W = 2 or H/W = 8). The maximum heat transfer enhancement coefficient of synthetic jets is found to be 74.7% higher than that of the corresponding steady jet.

Acoustic and mixing characteristic of CD nozzle with inverted triangular tabs

ABSTRACTIn this paper, we study the pressure energy decay, acoustic and mixing characteristics of non-circular jet with inverted triangular tabs at different ranges of aspect ratio. The centre line pitot pressure profile of the inverted triangular tab and ordinary tab shows that the decay of the jet from elliptical jet with inverted tab is faster than the jet from circular jet. When the aspect ratio of nozzle increased, the core length of the jet changes significantly due to the pressure loss. At different aspect ratios, the shock structure shows a prominent change with respect to the mixing promotion. The screech frequency of the jet noise gives appreciable change as the nozzle pressure is increased, and nearly 20–30% of decrease is witnessed in the magnitude of screech frequency. Introduction of inverted triangular tab jet modifies the shock cell formation which extensively changes the screech amplitude due to axis switching.

PIV Measurements in the Near and Intermediate Field Regions of Jets Issuing from Eight Different Nozzle Geometries

An experimental study was conducted to investigate the effect of nozzle geometry on the mixing characteristics and turbulent transport phenomena in turbulent jets. The nozzle geometry examined were round, square, cross, eight-corner star, six-lobe daisy, equilateral triangle as well as ellipse and rectangle each with aspect ratio of 2. The jets were produced from sharp linear contoured nozzles which may be considered intermediate to the more widely studied smooth contraction and orifice nozzles. A high resolution particle image velocimetry was used to conduct detailed velocity measurements in the near and intermediate regions. It was observed that the lengths of the potential cores and the growth rates of turbulence intensities on the jet centerline are comparable with those of the orifice jets. The results indicate that the decay and spreading rates are lower than reported for orifice jets but higher than results for smooth contoured jets. The jets issuing from the elliptic and rectangular nozzles have the best mixing performance while the least effective mixing was observed in the star jet. The distributions of the Reynolds stresses and turbulent diffusion clearly showed that turbulent transport phenomena are quite sensitive to nozzle geometry. Due to the specific shape of triangular and daisy jets, the profiles of mean velocity and turbulent quantities are close to each other in their minor and major planes while in the elliptic and rectangular jets are considerably different. They also exhibit more isotropic behavior compared to the elliptic and rectangular jets. In spite of significant effects of nozzle geometry on mean velocity and turbulent quantities, the integral length scales are independent of changes in nozzle geometry.

Heat transfer characteristics of impinging jets: The influence of unsteadiness with different waveforms

A series of experiments are conducted in which specially designed periodic air jets are applied to a heated surface for the purpose of enhancing heat transfer relative to the corresponding steady air jet. The periodic jets are produced by a mass flow rate controller. The experiments are performed for steady jets and for specially designed periodic jets, including a combination of sinusoidal, triangular and rectangular jets at frequencies from 1.25 to 20Hz, the triangular signal having a different symmetry (representing the ratio of time to increasing velocity in one cycle to total cycle time) and the rectangular jets having a variable duty cycle (representing the ratio of the pulse cycle on-time to off-time) at frequencies of 10Hz and 20Hz. Various unsteady jets show distinguishing frequency dependences and the step change, i.e. the sudden increase or decrease of signal, shows some advantageous influence on heat transfer improvement, especially negative step change. Therefore, the enhancement of combined signals lies between the performances of the individual signals. The enhancement for triangular (or sinusoidal) plus rectangular signals shows some improved performance compared with that of rectangular plus triangular (or sinusoidal) signals. The heat transfers are enhanced as Strouhal number increases from 0.004 to 0.068 on the whole for impinging jet with such combined signals. The signals of triangular jet with symmetry parameter of 0 and 1 have improved heat transfer, and the latter has a slightly better result than the former. The instantaneous changing rate of velocity also has an influence on heat transfer improvements. Thus the duty cycle of 1:2 has the best performance in terms of heat transfer enhancement in this study.

Liquid jet breakup for non-circular orifices under low pressures

This study uses a high-speed visualization technique to investigate the breakup process and flow behavior of low pressure water jets issued from non-circular orifices including square, triangular, and rectangular shapes. These orifices have approximately the same sectional areas. Stability curve and Ohnesorge chart are employed to make a comparison with circular jets discharged from a circular orifice of the same sectional area. The analysis is carried out for gauge pressures varying from 0.1psi to 70psi with small pressure steps corresponding to a range from 0.7kPa to 482.6kPa in metric units. Axis-switching phenomenon is observed and analyzed through calculating the axis-switching wavelength and oscillation frequency for rectangular jets. It is found that results for circular jets agreed well with classic theory. Non-circular jets demonstrate enhanced instabilities as a whole compared to circular jets. The different behaviors of non-circular jets are reasonably explained by Rayleigh’s oscillation theory. Axis-switching and aspect-ratio effect in rectangular jets is found to slow down the increase of breakup-length in the Rayleigh breakup regime. Square and triangular jets are more susceptible to wind effects and they are more unstable especially at higher pressure conditions. This can be concluded from the shorter breakup-length and narrower transitional region from the Rayleigh regime to the wind-induced regime as compared to the circular and rectangular jets. Axis-switching wavelength of the rectangular jets is found to increase linearly with increasing jet velocity and oscillation frequency decreases correspondingly.

Effect of noncircular orifice plates on the near flow field of turbulent free jets

In this paper, we experimentally investigate the near-field flow characteristics of turbulent free jets respectively issued from circular, triangular, diamond, rectangular, and notched-rectangular orifice plates into air surroundings. All the orifice plates have identical opening areas or equivalent diameters (De) and their aspect ratios (AR) range from 1 to 6.5. Planar particle image velocimetry (PIV) is used to measure the velocity field at the same Reynolds number of Re = 5 × 104, where Re = UeDe/v with Ue being the exit bulk velocity and v the kinematic viscosity of fluid. The mean and turbulent velocity fields of all the five jets are compared in detail. Results show that the noncircular jets can enhance the entrainment rate, reflected by the higher acceleration rates of mean velocity decay and spread, shorten the length of the unmixed core, expedite the increase of turbulent intensity compared with the circular counterpart shortened unmixed core, and increase turbulent intensity comparing to the circular counterpart. Among the five jets, the rectangular jet (AR = 6.5) produces the greatest decay rate of the near-field mean velocity, postpones the position at which the `axis-switching' phenomenon occurs. This supports that axis switching phenomenon strongly depends on jet initial conditions. In addition, the hump in the centerline variation of the turbulence intensity is observed in the rectangular and triangular jets, but not in the circular jet, nor in diamond jet nor in notched-rectangular jet.

Breakup of liquid jets from non-circular orifices

The purpose of this investigation is to study the effect of the orifice geometry on liquid breakup. In order to develop a better understanding of the liquid jet breakup, investigations were carried out in two steps—study of low-pressure liquid jet breakup and high-pressure fuel atomization. This paper presents the experimental investigations conducted to study the flow behavior of low-pressure water jets emanating from orifices with non-circular geometries, including rectangular, square, and triangular shapes and draws a comparison with the flow behavior of circular jets. The orifices had approximately same cross-sectional areas and were machined by electro-discharge machining process in stainless steel discs. The liquid jets were discharged in the vertical direction in atmospheric air at room temperature and pressure conditions. The analysis was carried out for gage pressures varying from 0 to 1,000 psi (absolute pressures from 0.10 to 6.99 MPa). The flow behavior was analyzed using high-speed visualization techniques. To draw a comparison between flow behavior from circular and non-circular orifices, jet breakup length and width were measured. The flow characteristics were analyzed from different directions, including looking at the flow from the straight edges of the orifices as well as their sharp corners. The non-circular geometric jets demonstrated enhanced instability as compared to the circular jets. This has been attributed to the axis-switching phenomenon exhibited by them. As a result, the non-circular jets yielded shorter breakup lengths as compared to the circular jets. In order to demonstrate the presence of axis-switching phenomenon in square and triangular jets, the jet widths were plotted along the axial direction. This technique clearly demonstrated the axis switching occurring in square and triangular jets, which was not clearly visible unlike the case of rectangular jets. To conclude, non-circular geometry induces greater instabilities in the liquid jets, thereby leading to faster disintegration. Thus, non-circular orifice geometries can provide a cheaper solution of improving liquid breakup and thus may enhance fuel atomization as compared to the precise manufacturing techniques of drilling smaller orifices or using costly elevated fuel injection pressure systems.

Particle image velocimetry investigation on mixing enhancement of non-circular sharp edge nozzles

An experimental study using Particle Image Velocimetry (PIV) on free jets issuing from different orifice plate (OP) nozzles is reported. Mean velocity, turbulence intensity and higher order profiles relevant for large and small scale mixing are considered in the near field and interaction zone (0<X/D<20). This is done to determine mixing enhancement due to rectangular, squared, elliptic and triangular nozzles in comparison to circular nozzle results in two orthogonal planes. The effect of Reynolds number on the differences among the nozzle shapes is also considered by performing measurements just after laminar–turbulent transition (Re=8000) and in the fully turbulent regime (Re=35,000). The results at low Reynolds number show two classes of jets, i.e. at one side, those closer to axial-symmetric conditions, as circular, square and triangular jets, whereas on the other side those with elongated nozzles as rectangular and elliptic. The reason for the different behavior of the latter is connected to the phenomenon of axis-switching which allows a rearrangement of turbulence over the different velocity components and directions. However, for the highest Reynolds number investigated, all nozzles show similar behavior especially in the jet far field (X/D>10), thus suggesting a significant Reynolds number dependence of the results.

PIV measurements of turbulent jets issuing from triangular and circular orifice plates

The present study experimentally investigated the near-field flow mixing characteristics of two turbulent jets issuing from equilateral triangular and circular orifice plates into effectively unbounded surroundings, respectively. Planar particle image velocimetry (PIV) was applied to measure the velocity field at the same Reynolds number of Re=50,000, where Re = U e D e/ν with U e being the exit bulk velocity and ν the kinematic viscosity of fluid, D e the equivalent diameters. The instantaneous velocity, mean velocity, Reynolds stresses were obtained. From the mean velocity field, the centreline velocity decay rate and half-velocity width were derived. Comparing the mixing characteristics of the two jets, it is found that the triangular jet has a faster mixing rate than the circular counterpart. The triangular jet entrainments with the ambient fluid at a higher rate in the near field. This is evidenced by a shorter unmixed core, faster Reynolds stress and centreline turbulence intensity growth. The primary coherent structures in the near field are found to break down more rapidly in the triangular jet as compared to the circular jet. Over the entire measurement region, the triangular jet maintained a higher rate of decay and spread. Moreover, all components of Reynolds stress of the triangular jet appear to reach their peaks earlier, and then decay more rapidly than those of the circular jet. In addition, the axis-switching phenomenon is observed in the triangular jet.

Numerical Study of Thermal Radiation Effect on Confined Turbulent Free Triangular Jets

The present study investigates the effects of thermal radiation on turbulent free triangular jets. Finite volume method is applied for solving mass, momentum, and energy equations simultaneously. Discrete ordinate method is used to determine radiation transfer equation (RTE). Results are presented in terms of velocity, kinetic energy, and its dissipation rate fields. Results show that thermal radiation speeds the development of velocity on the jet axis and enhances kinetic energy; therefore, when radiation is added to free jet its mixing power, due to extra kinetic energy, increases.

A METHOD TO CALCULATE PRESSURE PEAKS BASED ON FREE SURFACE SHAPE: PRELIMINARY RESULTS

Impulsive loads are difficult to predict due to the extremely non linear response to incident wave conditions. This behavior is related to air dynamics and local wave shape. The present study focuses on the latter.We propose a new method to predict pressure peaks generated during breaking wave impacts. In this method, the plunging jet is assimilated to two equivalent triangular jets (wedge impact) with variable inclination in time. The basic case of wedge impact is first studied in the paper. Semi empirical laws relating pressure peak and incident angle are derived based on numerical results obtained with a Navier-Stokes model . The more general case of a breaking wave is then investigated. By making an analogy with the wedge impact case and inverting the relation obtained before, we computed the location where the equivalent angles have to be taken on the free surface. We show that these points correspond to the minimum curvature section on the free surface. In another simulation of a breaking wave, we finally show how the relation can be applied to give a first approximation of the pressure peak only based on the free surface local shape.

Mean Streamwise Centerline Velocity Decay and Entrainment in Triangular and Circular Jets

The results of an experimental investigation of triangular and circular jets of air issuing into still-air surroundings are presented. Two isosceles triangular jets, issuing from sharp-edged orifices with apex angles of 30 and 160 deg, a sharp-edged orifice circular jet, and a contoured nozzle circular jet, were used for the study. The orifices and nozzle had the same exit area. The Reynolds number, based on the equivalent diameter of the triangular orifices (or diameter of the circular orifice or nozzle), was in the jets. An x–array hot-wire probe and a pitot-static tube were used to acquire the data. The results show that the 160 deg triangular jet has a higher mean streamwise centerline velocity decay rate but a lower mass entrainment rate than the 30 deg triangular jet. Also, the preferred mode Strouhal numbers for the 160 and 30 deg triangular jets were found to be 0.96 and 0.53, respectively. The autocorrelation coefficient distribution exhibits long tails in the 160 deg triangular jet, but it is periodic in the 30 deg triangular jet. Contour maps of the mean streamwise velocity, from which a faster development of the 160 deg triangular jet can be deduced, show changes in the shape of the triangular jets.

Large Eddy Simulation of an Initially-Confined Triangular Oscillating Jet

This paper reports the first large eddy simulation (LES) of a self-excited oscillating triangular jet (OTJ) issuing from a fluidic nozzle that consists of a small triangular orifice inlet followed by a large circular chamber and an orifice outlet. The case simulated is identical to that measured experimentally by England et al. (Exp Fluids 48(1):69–80, 2010). The present prediction agrees well with the previous measurement. The simulation reveals that the central oscillating jet exhibits axis-switching in the cross-section and rotates by 60° approximately over a downstream distance of x = 0.5D (chamber diameter). Three strong longitudinal vortices occur associated with the three vertices of the inlet triangle. These vortices strongly interact with the central jet and also the surroundings, in the region at x/D ≤ 1, and appear to merge finally with the outer secondary swirling flow. These observations are consistent with the deduction from previous experiments.