Low-pressure Zone Research Articles

Paradoxical Infective Endocarditis of the Right Coronary Aortic Cusp in a Restrictive Ventricular Septal Defect

We present the case of a 35-year-old female with small restrictive ventricular septal defect (VSD) presenting with prolonged fever for the last 1 month with vegetation on the right coronary cusp (RCC) of the aortic valve with flail aortic leaflet causing severe aortic regurgitation (AR). Her echocardiography done 1 year back had revealed the presence of small restrictive VSD with a gradient of 80 mm Hg without any prolapse of RCC or presence of AR. She did not have any early diastolic murmur of AR during 3 monthly routine follow-up in the cardiology outpatient department suggestive of previous aortic valve prolapse with AR in the aforesaid period before the infective endocarditis episode. Common sites of the vegetation in small restrictive VSD are right ventricular side of the interventricular septum, undersurface of the tricuspid valve, free wall of the right ventricle, and rarely the pulmonary valve on the low-pressure site of the shunt where the turbulent jet containing the bacteria slows down, and bacteria adhere the underlying endocardium. Normally, vegetation across any turbulent jet does not occur on the high-pressure site due to the reason that bacteria can not adhere to the wall across the turbulent jet in high-pressure zone, which sweeps away all the bacteria from the high-pressure zone to low-pressure zone. Paradoxical finding in our case was that vegetation was noted on the RCC of the aortic valve which was a high-pressure zone, which may be explained by only Bernoulli's phenomenon. Our case illustrates paradoxical vegetation on the RCC of the aortic leaflet in a patient with small restrictive VSD and is also a unique demonstration of left-sided endocarditis in a patient with left-to-right shunt.

Molecular simulation of C2H4/CO2/N2/O2 adsorption characteristics in lignite and anthracite

As an index gas of spontaneous combustion, C2H4 has been used in several coal mines, but its adsorption on residual coal during the process from generation to sampling has an impact on evaluation. The molecular structure models of lignite and anthracite were constructed through molecular mechanics and dynamics, and the Grand Canonical Monte Carlo systems were used to simulate the adsorption of C2H4 and other common gases on lignite and anthracite at temperatures of 288.15–318.15 K. The order of adsorption capacity was CO2 > C2H4 > O2 > N2 in the lignite and anthracite molecular models within the low-pressure zone. When the pressure increases, the adsorption capacity of O2 and N2 exceeded that of C2H4. The C2H4 and CO2 have similar and concentrated adsorption sites, and it is easier to reach the limit adsorption capacity; O2 and N2 have similar adsorption sites, the number of sites is much more than that of C2H4 and CO2, and their limit adsorption capacities are larger than those of C2H4 and CO2. When C2H4 is monitored in a goaf, its concentration is not quite accurate because of the adsorption of residual coal, which is different from the detected temperature of the C2H4 concentration obtained from the experiment. This is of great significance to further experiments and more on-site data statistics to fix the problem for coal mines.

Investigation of Pressure Oscillation and Cavitation Characteristics for Submerged Self-Resonating Waterjet

The cavitation phenomenon of the self-resonating waterjet for the modulation of erosion characteristics is investigated in this paper. A three-dimensional computational fluid dynamics (CFD) model was developed to analyze the unsteady characteristics of the self-resonating jet. The numerical model employs the mixture two-phase model, coupling the realizable turbulence model and Schnerr–Sauer cavitation model. Collected data from experimental tests were used to validate the model. Results of numerical simulations and experimental data frequency bands obtained by the Fast Fourier transform (FFT) method were in very good agreement. For better understanding the physical phenomena, the velocity, the pressure distributions, and the cavitation characteristics were investigated. The obtained results show that the sudden change of the flow velocity at the outlet of the nozzle leads to the forms of the low-pressure zone. When the pressure at the low-pressure zone is lower than the vapor pressure, the cavitation occurs. The flow field structure of the waterjet can be directly perceived through simulation, which can provide theoretical support for realizing the modulation of the erosion characteristics, optimizing nozzle structure.

Airflow-Assisted Impact of Drops of Various Viscosities: The Role of Viscous Dissipation, Normal Imposed Pressure, and Shear Flow of Air.

The role of liquid viscosity on the spreading for an airflow-assisted impact of drops on a surface is investigated. The spreading diameter is found to increase with the Reynolds number of the airflow (Reair) for a given viscosity and impact Weber number (We) compared to the still air. The increment is higher at a low We for viscous drops, whereas the effect of Reair dominates at the intermediate We as the viscosity decreases. Two extra forces, the normal imposed pressure and shear force of air, act on the drop and influence the spreading along with the viscous dissipation. The drop's curvature decreases depending on the viscosity and impact velocity while spreading. Large-scale eddies near the drop-surface region are observed due to the separation of the incident airflow. The formation of eddies signifies low-pressure zones, which extract the trapped air, causing the spreading diameter of the viscous drop to increase at a low We. With the increase in the We, the lamella thickness of low-viscosity drops decreases and is pushed out by the air shear causing the spreading factor to increase. The boundary layer thickness is estimated using the energy balance method to predict the maximum spreading factor. The prediction compares well with the experimental one for higher viscosities. The accuracy improves when the effect of low pressure is incorporated. To confirm, the experimental spreading is compared with that obtained from three existing models, and one, which considers the influence, is observed to provide a better prediction.

Study of the Effect of Vertical Airfoil Endplates on Diffusers in Vehicle Aerodynamics

Diffusers and the floor ahead of them create the majority of the downforce a vehicle creates. Outside motorsports, the diffuser is relatively unused, although its interaction with the ground is a consistent field of study owing to the aerodynamic benefits. The diffuser flow behavior is governed by three fluid-mechanical mechanisms: ground interaction, underbody upsweep, and diffuser upsweep. In addition, four different flow regimes appear when varying ride height, the vortices of which have great importance on downforce generation. The present study focuses on the diffuser’s fluid-dynamic characteristics undertaken within an academic framework with the objective of finding and understanding a high level of performance in these elements. Once the functioning of diffusers has been analyzed and understood, a new configuration is proposed: rear vertical airfoil endplates. The aim of the paper is to study the effect in performance of vertical airfoil endplates on diffusers in vehicle aerodynamics in a simplified geometry. The candidate to this geometry is the inversed Ahmed body, a geometry that is used as a model that simulates the flow behavior of car diffusers. Three different diffuser configurations are performed, namely 0° diffuser, 25° diffuser, and in the third case vertically installed rear vertical airfoil endplates are added to the 25° diffuser Ahmed body to change the flow field. These analyses are carried out by using open-source CFD simulation software OpenFOAM. An inlet velocity of 20 m/s is considered, as this is a typical velocity when cornering in motorsport. It is concluded that the 25° diffuser configuration generated more downforce than the 0° diffuser, which makes sense as the aim of adding a diffuser is to increase the amount of downforce produced. In addition, and as a result of the newly proposed configuration, the 25° diffuser Ahmed body with the vertical airfoil endplates emerges in a substantial increase of downforce thanks to the low-pressure zone generated at the back of the body.

Hybrid Flow Control on Boundary Layer Ingestion Inlet

For the boundary layer ingestion (BLI) inlet, how to control the flow is very important to improve the quality of the air flow at the outlet. In this paper, the research on the passive flow control is carried out by using rectangular straight spoiler blades, and the active flow control is carried out by using the blowing pipes. Finally, the effect of hybrid flow control is explored by combining the passive flow control device and the active flow control device. The results show that the spoiler blades can squeeze the low pressure zone to both sides of the outlet and reduce the area of the low pressure zone. The steady-state circumferential distortion coefficient of the outlet can be reduced by 66.7% by adopting the appropriate passive flow control scheme. The blowing rate of active flow control has a significant effect on the flow control effect. The optimal hybrid flow control scheme is obtained by optimization and the steady-state circumferential distortion coefficient can be reduced by 76.8% when the blowing flow rate is 0.67% of the inlet flow.

Analysis of wellbore stability by pore pressure prediction using seismic velocity

Borehole problems result in the wastage of huge expenditures in petroleum industry. One of the major challenges is to keep the borehole intact at a particular location and prevent it from falling in reactive shale in high- or low-pressure zones. To convert seismic velocity to pore pressure, the modified Eaton's equation is widely used. A guideline was prepared using both stochastic and non-uniform parameter distributions. Pore pressure and fracture pressure were calculated using a modified version of Eaton's and Mathew and Kelly's methods. To validate the results, geomechanical models were developed based on good correlation. Different regions in the eastern state of India at Tripura were taken into consideration and pore pressure was estimated for the regions of Kathalchari and Ambassa by plotting pressures. The actual pore pressure predicted in Tripura was calculated using seis P and seis P3, the indigenous software which is a modified version of Eaton's method and Mathew and Kelly's method, and the pore pressure from our method matches the calculated Repeat Formation Test (RFT) data from wells.

Molecular simulation of gases competitive adsorption in lignite and analysis of original CO desorption

To study the adsorption characteristics of CO, CO2, N2, O2, and their binary-components in lignite coal, reveal the influence of CO2 or N2 injection and air leakage on the desorption of CO in goafs, a lignite model (C206H206N2O44) was established, and the supercell structure was optimized under temperatures of 288.15–318.15 K for molecular simulation. Based on molecular dynamics, the Grand Canonical Monte Carlo method was used to simulate the adsorption characteristics and the Langmuir equation was used to fit the adsorption isotherms of gases. The results show that for single-components, the order of adsorption capacity is CO2 > CO > O2 > N2. For binary-components, the competitive adsorption capacities of CO2 and CO are approximate. In the low-pressure zone, the competitive adsorption capacity of CO2 is stronger than that of CO, and the CO is stronger than N2 or O2. From the simulation, it can be seen that CO2, N2 or O2 will occupy adsorption sites, causing CO desorption. Therefore, to prevent the desorption of the original CO in the goaf, it is not suitable to use CO2 or N2 injection for fire prevention, and the air leakage at the working faces need to be controlled.

An Investigation of Aerodynamic Characteristics of Three Bluff Bodies in Close Longitudinal Proximity - Part 2

<div class="section abstract"><div class="htmlview paragraph">The work described in this paper is a continuation of an investigation into the effects of systematic changes in upper-body geometry on the aerodynamic drag of passenger-car-like bluff-body models in close longitudinal proximity and operating in platoon formations. The original work, presented in SAE paper 2019-01-0659, showed measurements of the aerodynamic drag of individual models within three-model platoons and for which each model was tested in three different upper-body configurations This provided a data-set of 27 platoon configurations to compare with the three baseline conditions of the isolated models. The work contrasted with other published platooning research in which the spacing, between homogeneous models in the platoons, was the only variable to be considered.</div><div class="htmlview paragraph">In this publication the results of further wind tunnel tests, using the same models as before but in two-model platoons, providing a further 9 test configurations are compared with the original data. In addition, the results of CFD analyses for both the two and three-model platoon configurations are reported to help provide a more detailed and illustrated explanation of the modification of flow regimes and subsequent forces due to close-proximity.</div><div class="htmlview paragraph">The most significant influence on drag of the proximity tests was shown to be the interference on upstream wakes due to the presence of a following model. The shielding effect provided to trailing models also resulted in a drag reduction by reducing pressure drag on upright nose surfaces. But shielding also resulted in a drag penalty by reducing flow velocity over the radiused leading edges, particularly of the A-pillars thereby reducing a low pressure zone which, in unobstructed flow, yields a drag reduction for the Windsor model.</div></div>

Solving optimal reactive power problem by hurricane search optimization algorithm

In this paper Proposed Hurricane Search Optimization (HSO) algorithm is proposed to solve optimal reactive power problem. An upward motion of air is caused due to release of heat which creates a low-pressure zone and by the rotation of the earth that is set into spin. In this spiraling airflow when energy is high then hurricane is created. Projected Hurricane Search Optimization (HSO) algorithm<strong> </strong>design is based on the examination of the horizontal wind structure in a hurricane and how the wind parcels the progression in the neighboring atmosphere. A mixture of wind models has been developed for past few years to Backtesting and to compute hurricane exterior wind fields. Proposed Hurricane Search Optimization (HSO) algorithm has been tested in standard IEEE 30, 57bus test systems and simulation results show the projected algorithm reduced the real power loss considerably.

Petrogenesis of the gabbronorite sill hosted Fe-Ti oxide ore bodies from the eastern part of Chotanagpur granite Gneissic Complex, India

Magmatic Fe-Ti oxide ore bodies of the eastern Chotanagpur Granite Gneiss Complex (CGGC), India occur as massive conformable lenses within a gabbronorite sill. The occurrence, lithological association, mineralogy, and geochemistry of the Fe-Ti oxide ore bodies are significantly different from the typical Fe-Ti oxide deposits associated with anorthosite complexes and mafic- ultramafic complexes. Textural evidence and mineral chemistry suggest mostly simultaneous fractional crystallization of the comprising minerals e.g. titanomagnetite, ilmenite and magnesio-hercynite. The temperature and fO2 conditions of re-equilibration are calculated using the compositions of ilmenite and pre-exsolved titanomagnetite pairs. Extrapolation of the data along ulvospinel isopleths reveals the probable original magmatic conditions e.g. temperature ~ 900 °C and fO2 ~ ΔFMQ + 2. The ore forming melt calculated by ‘equilibrium distribution method’ shows no crustal contamination and has a trace elemental pattern similar to typical enriched basaltic melts e.g. ferropicrites, alkali basalts, OIB and EMORB. High Ti and Zr contents of the melt suggest a possible within plate tectonic setting and enrichment in HFSEs and LREEs suggest that the parent melt could be generated from an enriched mantle source by low degree partial melting of garnet-peridotite layer of the upper mantle. The ‘quantitative fractional crystallization modelling’ indicates that early crystallization of olivine, pyroxenes, plagioclase and ilmenite from an enriched basaltic melt similar to EMORB (most fit melt) led to a condition of high oxygen fugacity and iron enrichment in the residual melt. The residual Fe-Ti rich melt moved to low pressure zones within the gabbronorite sill during late stage of D2 deformation, and later crystallized in the form of present ore bodies.

Formation and Stability of Thin Condensing Films on Structured Amphiphilic Surfaces.

We present a microamphiphilic surface to promote the formation of a thin, stable liquid film during condensation. The surface consists of a hydrophilic micropillar array with hydrophobic pillar tips and was made using photolithography, deep reactive ion etching, and liftoff. The hydrophobic tips prevent the liquid film from growing thick, thereby keeping the thermal resistance low without the cyclical growth and shedding process of dropwise condensation. The wetting behavior was modeled analytically, and the parameters required for film formation were determined and verified with ESEM experiments. When a surface filled with condensate and lacked a low-pressure zone for the water to leave, a rupture event occurred, and a large Wenzel droplet emerged to flood the surface irreversibly. A number of strategies were found to combat rupture events. Tilting the surface vertically and dipping in a liquid pool gave the condensate a low-pressure region and prevented rupture. Irreversible flooding can also be avoided by ensuring that the emerged droplet was a nonwetting, highly mobile Cassie droplet. Parameters for Cassie-stable amphiphilic surfaces were determined analytically, but the high aspect ratios required prevented the manufacture of these surfaces for this study. Instead a hierarchical design was presented that demonstrated emerged Cassie droplets without challenging the manufacturing limits of the microfabrication procedure. This design avoided Wenzel droplet flooding without the need for a designated low-pressure zone. Additionally, sites for Cassie emergence could be engineered by removing a single pillar from the array at a designated location.

EXPERIMENTAL INVESTIGATION OF ENHANCEMENT IN EFFICIENCY OF CENTRIFUGAL PUMP BY REDUCTION IN CAVITATION OF PUMP

Cavitation phenomenon is basically a process formation of bubbles of a flowing liquid in a region where the pressure of the liquid falls below its vapour pressure and it is the most challenging fluid flow abnormalities leading to detrimental effects on both the centrifugal pump discharge characteristics as well as physical characteristics. In this low pressure zones are the first victims of cavitation. Due to cavitation pitting of impeller occurs and wear of internal walls of pumps occurs due to which there is creation of vibrations and noize are there. Due to this there is bad performance of centrifugal pump is there. Firstly, description of the centrifugal pump with its various parts are described after that pump characteristics and its important parameters are presented and discussed. Passive discharge (flow rate) control methods are utilized for improvement of flow rate and mechanical and volumetric and overall efficiency of the pump. Mechanical engineers is considering an important phenomenon which is known as Cavitation due to which there is decrease in centrifugal pump performance. There is also effect on head of the pump which is getting reduced due to cavitation phenomenon. In present experimental investigation the cavitation phenomenon is studied by starting and running the pump at various discharges and cavitating conditions of the centrifugal pump. Passive discharge (flow rate) control is realized using three different impeller blade leading edge angles namely 9.5 degrees, 16.5 degrees .and 22.5 degrees for reduction in the cavitation and increase the of the centrifugal pump performance at different applications namely, domestic, industrial applications of the centrifugal pump.

Study on Acid Corrosion Characteristics in Low-Pressure Stage Initial Condensation Zone of Supercritical H2O/CO2 Turbine

Compared with the traditional steam turbine, the supercritical H2O/CO2 turbine has a relatively high CO2 content in the working fluid. In the initial condensation zone, CO2 dissolves in the condensed water to form carbonic acid, which intensifies the corrosion of blade. In order to study the acid corrosion characteristics in the initial condensation zone of supercritical H2O/CO2 turbine, the acid corrosion rate of the blades in the initial condensation zone of supercritical H2O/CO2 turbine was calculated and analyzed based on the numerical model of non-equilibrium condensation flow and a numerical model of CO2 corrosion reaction. The results show that the temperature, pressure, proportion of CO2 in the gas phase and thickness of the solution on blade surface are the main factors affecting the acid corrosion rate in the initial condensation zone of the turbine. The influence of temperature and pressure is more significant. Overall, the acid corrosion rate decreases stage by stage.

Effect of Hub Gap on Expanding Stability of Centrifugal Compressor

In this paper, the possibility of using hub gap (“ HG ”for short) to suppress gas stall and expand the range of stable working condition of compressor is verified by numerical method. The research shows that when designing flow rate, HG increases, the efficiency and pressure ratio of model level decrease. When there is a large flow, the efficiency and pressure ratio of HG model are higher than those without HG. The larger HG is, the higher the efficiency and pressure ratio is. From the analysis of the expanding stability capacity, the model-level flow margin of small HG and large HG is 5% and 15% higher than that of models without HG, and the comprehensive stall margin is 6.87% and 23.59% higher on average. When operating at unstable working conditions, the action of HG causes the airflow in the high pressure zone to flow into the gap and out of the low pressure zone, which improves the flow distribution in the blade passage and makes the flow field stable. However, when operating near the design condition, the leakage flow and its mixing with the momentum of the mainstream are the main sources of aerodynamic loss. The larger HG is, the greater the pressure loss caused by the leakage flow is. Generally speaking, HG can play the role of compressor expansion stability, but at the cost of efficiency; The bigger HG is, the stronger the role of expanding stability is and the greater the efficiency loss is.

LES study on the working mechanism of large-scale precessing vortices and energy separation process of Ranque-Hilsch vortex tube

In this paper, a large eddy simulation model (LES) was adopted to analyse the large-scale precessing vortices and energy separation in a Ranque–Hilsch vortex tube. By comparing the time-averaged axial velocity field between the Laser Doppler velocimetry data and the numerical results, the feasibility of the LES model was confirmed. The 2D instant flow field presents two vortex structures of secondary circulation flow at the cold end, and precessing vortices inside the tube. It also reveals two opposite flows in the axial and radial directions, and the precessing vortices formed by the reverse flow turn towards the main flow. Then, the 3D coherent structure inside the vortex tube was obtained by the vortex identification method for the first time. The basic vortex structure inside the vortex tube consists of the vortex body, detached vortex, and fragmentised detached vortex. Through the evolution of the 3D vortex structure, it was found that the detached vortices experienced a life cycle of growth, shedding, fragmenting, and vanishing. Benefitting from the vortex shedding processes, the precessing vortices overcame the adverse radial pressure gradient and drove part of the reverse flow towards the main flow from the low-pressure zone to the high-pressure zone. Through these processes, the vortex core precession that drives the reciprocating motion of the gas parcels near the reverse flow boundary was established, and energy could be transferred from the inner layer to the outer layer through a heat pump cycle.

Influence of Impeller Gap Drainage Width on the Performance of Low Specific Speed Centrifugal Pump

The centrifugal pump is one of the most important pieces of energy-consuming equipment in various hydraulic engineering applications. This paper takes a low specific speed centrifugal pump as the research object. Based on the research method combining numerical calculation and experimental verification, the influence of the gap drainage structure on the performance of the low specific speed centrifugal pump and its internal flow field distribution were investigated. The flow field inside the low specific speed centrifugal pump impeller under different gap widths was studied. The comparison between the numerical calculation results and the experimental results confirms that the numerical calculations in this paper have high accuracy. It was found that the gap drainage will reduce the head of the low specific speed centrifugal pump, but increase its hydraulic efficiency. Using a smaller gap width could greatly improve the performance of the low specific speed centrifugal pump on the basis of a slight reduction in the head. The high-pressure leakage flow at the gap flows from the blade pressure surface to the suction surface can effectively suppress the low-pressure area at the impeller inlet. The flow rate of the high-pressure leakage flow increases with the gap width. Excessive gap width may cause a low-pressure zone at the inlet of the previous flow passage. These results could serve as a reference for the subsequent gap design to further improve the operating stability of the low specific speed centrifugal pump.

Swimming behavior of newly hatched larvae of six decapod species (Crustacea: Decapoda)

Abstract Crustacean decapod larvae have developed several adaptations to maximize their survival, including swimming behavior. Swimming improves larvae dispersal and contributes to their response to environmental stresses, including variations in abiotic factors, presence of predators, and search for food. Data on larval behavior can also assist in studies on conservation and in species management in aquaculture. Unfortunately, swimming behavior remains unstudied in many species. The present work aims to analyze the swimming behavior in newly hatched larvae of six common decapod crustaceans in coastal Southeast Brazil (Macrobrachium acanthurus, Macrobrachium olfersii, Emerita brasiliensis, Ucides cordatus, Minuca rapax, and Callinectes danae). The analysis included tests with larval responses to four isolated stimuli: gravity (geotaxis), vertical salinity gradients, low-pressure zones, and presence of the planktivorous fish, Atherinella brasiliensis (only for C. danae and M. rapax). The first two and the last two stimuli were used as indicators of dispersal and defensive behaviors, respectively. All larvae preferred water depth with higher salinity levels. Additionally, negative geotaxis was observed in M. olfersii, M. acanthurus, U. cordatus, and C. danae, being stronger in the last. Both Macrobrachium larvae responded to low-pressure zones, promptly moving away. Callinectes danae and M. rapax larvae avoided contact with the predatory fish by creating avoidance zones around it, even in the absence of light. This is an active defensive behavior that has never been reported for the newly hatched larvae of these two species.

Characterization of aerodynamic performance of wind-lens turbine using high-fidelity CFD simulations

Wind-lens turbines (WLTs) exhibit the prospect of a higher output power and more suitability for urban areas in comparison to bare wind turbines. The wind-lens typically comprises a diffuser shroud coupled with a flange appended to the exit periphery of the shroud. Wind-lenses can boost the velocity of the incoming wind through the turbine rotor owing to the creation of a low-pressure zone downstream the flanged diffuser. In this paper, the aerodynamic performance of the wind-lens is computationally assessed using high-fidelity transient CFD simulations for shrouds with different profiles, aiming to assess the effect of change of some design parameters such as length, area ratio and flange height of the diffuser shroud on the power augmentation. The power coefficient (Cp)is calculated by solving the URANS equations with the aid of the SST k–ω model. Furthermore, comparisons with experimental data for validation are accomplished to prove that the proposed methodology could be able to precisely predict the aerodynamic behavior of the wind-lens turbine. The results affirm that wind-lens with cycloidal profile yield an augmentation of about 58% increase in power coefficient compared to bare wind turbine of the same rotor swept-area. It is also emphasized that diffusers (cycloid type) of small length could achieve a twice increase in power coefficient while maintaining large flange heights.

Splashing of liquid droplet on a vibrating substrate

The unsteady axisymmetric problem of a liquid drop impacting onto a rigid vibrating substrate is studied. Initially, the drop is spherical and touches the flat substrate at a single point. Then, the substrate starts to move toward the drop and vibrate with a small amplitude and high frequency. The early stage of the impact is studied by using the potential flow theory and the Wagner approach in dimensionless variables. The effect of the substrate vibration on the drop impact is described by a single parameter. It is shown that the vibration of the substrate leads to oscillations of the pressure in the contact region. The low-pressure zone periodically appears in the wetted part of the substrate. The low-pressure zone can approach the contact line, which may lead to ventilation with separation of the liquid from the substrate. The magnitude of the low pressure grows in time. The acceleration of the contact line oscillates with time, leading to splashing of the droplet with the local increase of the thickness of the spray jet sheet at a distance from the contact line. The phase shift of the substrate vibration with respect to the impact instant is not studied. Splashing can be produced only by a forced vibration of the substrate. The impact onto an elastically supported rigid plate does not produce splashing. The obtained results and the theoretical model of the initial stage of drop impact are valid for certain ranges of parameters of the problem.