Launching Process Research Articles

Analysis of motion interference characteristics of underwater vehicles salvo based on the RBF Neural Network

Compared with the launch process of a single underwater vehicle, the salvo of multiple vehicles is more complex and needs to be more deeply studied. When the first vehicle is launched, it will disturb the flow field and affect the attitudes and trajectories of the subsequent vehicles. If the impact range is not clearly defined, the launch safety will be threatened. In this paper, we outline the underwater salvo process of two vehicles. A RBF (radial basis function) neural network model is established, which is driven by data generated through numerical simulation. The model is applied to predict the interference variation law of motion characteristic variables that the first vehicle to the second under different launch conditions. The results show that the RBF neural network model can predict the interference of the motion characteristic variables that the first vehicle to the second vehicle in the process of salvo, which is more effective and accurate than the numerical simulation and experimental methods. In addition, the results reveal the influence of the first vehicle on the deflection angle and displacement of the second vehicle under different launch parameters, in which the launch time interval is the most sensitive factor affecting the motion characteristics of the vehicle.

Armature Electromagnetic Force Extrapolation Prediction Method for Electromagnetic Railgun at High Speed

The analysis and calculation of the armature electromagnetic force is the premise of studying the dynamic characteristics of the electromagnetic railgun. Aiming at the problem of the numerical solution “pseudo-oscillation” at high speed, an extrapolation prediction method of armature electromagnetic force based on the Deep Belief Network-Deep Neural Network (DBN-DNN) is proposed. Firstly, the electromagnetic field control equation and armature dynamics equation, considering the influence of armature movement, are given, and the finite element simulation model of the electromagnetic railgun is established to analyze the dynamic characteristics and numerical solution stability of the armature electromagnetic force. Then, based on the stable numerical simulation data under different armature conductivities, a DBN-DNN method is proposed to realize the extrapolation prediction of the armature electromagnetic force under the standard conductance. Finally, the extrapolation prediction performance of the proposed method is tested by two electromagnetic railgun cases. Additionally, we further propose the training strategy of DBN-DNN parameters from solving armature electromagnetic force at low conductivity to standard conductivity. The armature electromagnetic force extrapolation prediction method for the whole launch process from low speed to high speed provides a new idea for the dynamic characteristic analysis of the high-speed electromagnetic railgun.

Numerical investigation on muzzle flow characteristics for small combustion chamber with embedded propelled body

Achieving a smaller size and lighter weight without affecting the launch performance is an important goal in the design of special launch equipment systems such as micro air vehicles and gun propulsion systems. An embedded structure is applied to small chamber systems to save launch space. This paper aims to illustrate the launch performance and muzzle flow characteristics of the embedded structure. The mathematical model of the launch process with a two-stage ignition is established. The muzzle flow model is used to simulate the launch process. The numerical method is verified by experiment. Numerical results indicate that a 21.1% space saving and a 4.2% muzzle velocity increase can be achieved by the embedded structure. The effect of the embedded structure on the muzzle flow is investigated. In the launch process, the Mach disk of the traditional structure travels farther, but that of the embedded structure catches up due to the greater velocity. The pressure oscillation of the embedded structure is larger, but the range of the oscillation is smaller. In the development process, compared with the traditional structure, the main parameters of the embedded structure, such as pressure and Mach number, are greater, which may lead to the launch risk. The findings will be applied to improve the design of small launchers.

The MURALES survey

This paper is the seventh work in the MUse RAdio Loud Emission lines Snapshot (MURALES) project series, presenting the results of observations obtained with the VLT/MUSE integral field spectrograph of 3C radio sources. Here, we discuss the optical spectral properties of the nuclei of 26 objects with 0.3 < z < 0.82 (median redshift 0.51). At these redshifts, the Hα and [N II] emission lines are not covered by optical spectra and alternative diagnostic diagrams are needed to separate the different spectroscopic sub-classes. We derived a robust spectroscopic classification into high and low-excitation galaxies (HEGs and LEGs) by only using the ratios of emission lines in the rest-frame UV and the blue portion of the spectra. A key result of this study is that FR II LEGs are also found at the highest level of radio power (up to L178 MHz ∼ 2 × 1035 erg s−1 Hz−1), placing them among the most luminous radio sources in the Universe. Furthermore, their fraction within the FR II RG population does not strongly depend on radio luminosity. This suggests that the jet properties in powerful FR II radio sources do not depend on the accretion mode or on the structure of the accretion disk – as would otherwise be expected if the jet launching process were due to the extraction of the rotational energy of the supermassive black hole. The alternative possibility of recurrent transitions between a LEG and a HEG phase is disfavored based on the variation timescales of the various active galactic nucleus (AGN) components.

Numerical Simulation of the Two-phase Flow of a Constant-pressure Rear-spray Low Recoil Weapon with Two Chambers

To study the effect of a constant-pressure rear-spray low recoil weapon with two chambers on weapon launch performance, based on two-phase flow theory, the valve-spring type constant-pressure rear-spray low recoil weapon firing process with two chambers was studied numerically. Considering the movement of the valve-spring system, a mathematical model of the weapon launch process combining the two-phase flow of gas and solid in the front and back chambers, the movement of the projectile and the transient flow of gas in the lateral rear nozzle is established. Using a 30 mm chain gun as an example, numerical simulation was carried out, and the distribution law of the flow field in the two chambers and the lateral rear nozzle during the firing of the weapon was obtained and compared with the internal flow field of the traditional weapon chamber. The results show that by reasonably matching parameters to control the flow of gunpowder gas in the two chambers, the recoil impulse can be reduced by 81.58% under the premise that the initial velocity of the projectile does not decrease, and the purpose of making full use of gunpowder gas energy to greatly reduce arms recoil is realized.

Mutual Fund Product Launch Process Setup and Automation: Streamlining Spreadsheet Workflows: A Case Study

The implication of technology is discussed in the study in a streamlined manner. The white paper presents a detailed case study that outlines the successful transformation of macro-heavy spreadsheets into a streamlined system to track the launch of a new mutual fund strategy. Gold source databases were associated before setting up procedures to assist business users in tracking the launch of new mutual fund strategies. Therefore, the empirical analysis is purposed toward analysing mutual fund product launch process setup and automation through a case study. Such feathers provide the basis for the introduction of mutual funds. The project required the creation of a gold source database from scratch, the implementation of effective procedures, and the use of software programs like Informatica and ServiceNow. Additionally, with the help of a streamlined case study method, it was possible to discuss the challenges of the mutual fund’s product development process. The strategy teams in the US and UK were analysed with a framework., and the framework and procedure were put into place accordingly. Furthermore, ServiceNow, which is a cloud-based platform was analysed for product development and Informatica was used in the project. Moreover, it was noted that the software aids businesses in automating and managing their HR, security, and customer support procedures. Thus, ServiceNow and Informatic were analysed from the lens of creating a product for mutual funds

Trajectory prediction of underwater launch equipment based on varying flow coefficient

In the underwater launch systems, a real-time prediction of the trajectory of the equipment out of the tube can provide accurate motion feedback for the closed-loop control. In this paper, using an analytical approach, a hydrodynamic mathematical model is developed for the open pipeline underwater launch system, along with an analysis of the coupling of pressure-flow variables influence mechanism on the trajectory. A time-varying coefficient-based prediction model for the equipment trajectory of the underwater launch process is developed for the compressible fluid and the strong transient characteristics of the fluid during the underwater launch process. Through the incorporation of the time-varying component of inertia into the flow coefficient, the interlinking relationship between the fluid, the pipe structure, and the equipment motion is clarified. This addresses the problem that the traditional steady-state hydrodynamic pipeline model cannot accurately describe the strong transient launch process. The experimental results show that, under typical firing conditions, the maximum error between the equipment motion velocity predicted by the mathematical model based on the time-varying flow coefficient and the measured velocity is 8.48%, with an error root mean square of 0.3035, proving the accuracy of the model based on the time-varying flow coefficient.

Ground Test and Numerical Simulation of Aerodynamic Interference of the Marsupial UAS

The marsupial unmanned aircraft system (UAS) consists of a large parent unmanned aerial vehicle (UAV) and multiple small children UAVs that can be launched and recovered in the air. The employment of marsupial UAS can expand the mission range of small UAVs and enhance the collaborative capabilities of small UAVs. However, the serious aerodynamic interference between the parent UAV and the child UAV will affect the flight safety during the launch and recovery process. In this paper, the interference characteristics of marsupial UAS is investigated through ground tests and CFD simulation. Ground tests compared the lift and power of the child UAV with and without parent UAV interference in different areas, and the simulation extended the experimental scope. Three specific interference regions above the parent UAV are defined, including the area above the rotors, the area above body and the transition area. In the first two aeras, the variation of the disturbed lift is more than 30% of the child UAV weight. In the transition aera, the child UAV will be subjected to significant lift variations and asymmetric moments. According to the interference characteristics of different regions, the safe flight boundaries and the appropriate paths of children UAVs are proposed.

Hydrodynamic Characteristics of Three-Bucket Jacket Foundation for Offshore Wind Turbines During the Lowering Process

The three-bucket jacket foundation is a new type of foundation for offshore wind turbine that has the advantages of fast construction speed and suitability for deep water. The study of the hoisting and launching process is of great significance to ensure construction safety in actual projects. In this paper, a new launching technology is proposed that is based on the foundation of the three-bucket jacket for offshore wind turbine. A complete time domain simulation of the launching process of three-bucket jacket foundation is carried out by a theoretical analysis combined with hydrodynamic software Moses. At the same time, the effects of different initial air storage and sea conditions on the motion response of the structure and the hoisting cable tension are studied. The results show that the motion response of the structure is the highest when it is lowered to 1.5 times the bucket height. The natural period of each degree of freedom of the structure increases with the increase of the lowering depth. The structural motion response and the hoisting cable tension vary greatly in the early phases of Stages I and III, smaller in Stage II, and gradually stabilize in the middle and late phases of Stage III.

Modeling efficiency and safety on an aircraft carrier flight deck

Aircraft carrier flight decks present high-risk mission-critical environments that need to be both efficient and safe. The concept of optimal manning, having just enough people to do the job safely and efficiently, is paramount in order to put the least amount of people at risk while not sacrificing mission effectiveness. To this end, an agent-based model, the optimal manning simulation (OMS) was developed, which specifically looks at the launch process of the flight deck in order to quantify the risk and efficiency of people working on the flight deck. OMS models different classes of crew members on the flight deck, aircraft, and resources like catapults. OMS measures safety through collisions or near-collisions of people and aircraft, as well as how long it takes to execute a launch cycle, the primary efficiency metric. Validation and sensitivity analyses provide confidence in OMS results. To demonstrate its utility, OMS is also used to predict how the future introduction of unmanned aerial vehicles could impact staffing and performance measures.

Experiment on gas flow field of large-caliber hypersonic balance gun in half-space

As one of the main methods to study the characteristics of an object, experiment is the main way to verify the correctness and reliability of numerical results. The hypersonic projectile near the ground launch involves many complex physical phenomena, so the ground surface has an important impact on the flight stability of the projectile and the structural characteristics of the gas flow field. In this paper, we carried out a whole process experiment of a hypersonic projectile from the bottom of the tube to the muzzle based on the 300 mm balance gun. The muzzle pressure and the initial velocity of the muzzle were monitored by the data acquisition system. We obtained the influence of the ground on the gas flow field of the hypersonic projectile through the overpressure data on the ground near the muzzle. Meanwhile, the dynamic characteristics of the launch process are recorded by high-speed photography. The experimental results show that the muzzle shock wave meets the ground, and the reflection phenomenon occurs, forming a wavefront with opposite directions of propagation. It makes the pressure in the lower half of the domain significantly higher than that in the upper half. By analyzing the experimental phenomena and experimental data, this paper shows the development characteristics of the projectile’s flow field, as well as the influence of the ground on the flow field and the motion stability of the projectile.

Time-Varying Inductance Gradient in Rails Based on Geometric Mean Distance

The inductance gradient is one of the most critical parameters in the electromagnetic rail launcher (ERL). It determines the electromagnetic force and efficiency in the ERL. In general, the inductance gradient in the rails is treated as a constant. However, the inductance gradient in the rails changes dynamically during the launching process. It is very important for the electromagnetic driving force in the launching process to accurately solve the time-varying inductance gradient. For this reason, a method for establishing the analytical calculation of the time-varying inductance gradient is proposed in this article. The results show that the application conditions of the proposed method are ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$s/w&gt;2$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$s/h&gt;1$ </tex-math></inline-formula> ), and the shortest side length of the rail must be greater than 20 mm. At last, in order to verify the applicability of this method, the inductance gradients in five different ERLs injected with the pulse current are calculated and the results obtained are compared with the FEA. The research shows that the inductance gradient in the initial stage changes significantly due to the rapidly changing current frequency. After an interval, it tends to be a constant, which is the result of the stabilization of the current. It is consistent with the results reported in the literature. And if the rail dimensions meet the applicable conditions, the maximum error between the method in this article and the FEA is less than 5%.

Orbital Launch Anomalies as Mechanisms of Motion of Space Rockets through MIRCE Space

The main objective of this paper is to briefly describe several orbital launches where space rockets of different types have either never made it to space or failed to deploy their payloads once they got there. The common denominator for a failure of each space rocket type, according to publicly available information provided by their management and sponsoring teams, was a launch anomaly. Based on the extremely short duration of all missions considered, the most probable mechanisms that caused orbital launch anomalies, in accordance to the MIRCE Science theory; have been induced into rockets by human actions during: design, production, assembly, transportation or launch processes. As the anomalies occurred on space rockets that are designed, produced and launched by different companies, located on different continents, it could be concluded that human errors are a generic phenomenon of the human race. The orbital launch anomalies observed in this paper are in agreement with the 5th Axiom of MIRCE Science that states, “Probability of human error in execution of any task is greater than zero”.

The development and applications of a controllable lander for in-situ, long-term observation of deep sea chemosynthetic communities

Understanding the evolution of chemosynthetic communities and environmental changes near fluid seepages in the deep sea requires in-situ long-term observation data. However, in-situ detection or sampling for the investigation of cold seeps, hydrothermal vents, and nearby chemosynthetic ecosystems, by manned submersibles and remotely operated vehicles (ROVs), has great restrictions in terms of time. The observation parameters of a free-fall mode Lander cannot be adjusted in real time because there is no communication channel once the Lander is separated from the vessel. A long-term ocean observation platform (LOOP), that uses a new controllable mode for launching and recovery with the aid of a research vessel and submarine vehicles, has been developed and used in the cold seep area of the South China Sea. The LOOP can be operated in an online real-time control mode allowing landing site selection and adjustment of observation parameters during the launching process, with subsequent switched to an offline stand-alone operation mode for long-term, continuous observation. The effective observation times were 375 days and 414 days, respectively, during the 2016 and 2018 deployments in the cold seep area in the South China Sea. Results of these deployments show that salinity and dissolved oxygen parameters have strong spatial heterogeneity in both the horizontal and vertical directions within the cold seep vent. The spatial heterogeneity of environmental parameters may be one of the main driving factors for the uneven spatial distribution of chemosynthetic communities in cold seep areas. Overall, the LOOP provides an innovative and controllable launching and recovery mode and is expected to become a universal underwater observation platform for in-situ, long-term, and continuous data acquisition.

Simulation research on the outlet cavity features in the underwater launching process

This paper analyzes the evolution of cavity features and pressure characteristics during the underwater launching process. The improved delayed eddy simulation (IDDES), energy equation, and overlapping grid technique are adopted. In addition, validation of the numerical approach and grid independence is carried out. The evolution of the multiphase flow field and pressure fluctuations near the launcher outlet are studied. Results show that the gas mass escaping from the tube expands and contracts, eventually breaking off with a jet that acts on the tail of the vehicle after the vehicle leaves the tube. Four major pressure fluctuations occurred near the launcher outlet, the first two of which are generated by the alternate expansion and contraction of the high-pressure gas mass, while the subsequent fluctuations mainly originate from the intermittent escape of the remaining gas mass inside the tube, the magnitude of the pressure fluctuations decreases gradually. As the Froude number increases, the scale of the escaping high-pressure gas mass expands significantly, while the dissipation rate of the fused gas mass at the launch tube outlet also increases, the evolution mechanism of multiphase is more complex.

COMPETITIVE STRATEGIES FOR CREATING THE COMPANY'S IMAGE

This article presents the strategic perspectives for developing the company's image. Corporate image is a powerful source of competitive advantage that enables a company to generate long-term added value. Through the operational framework of brand management, the company addresses image strategically, starting with planning and ending with monitoring and continuous improvement of image aspects. Throughout the life cycle of the enterprise, the company’s brand concept goes through the process of launching, developing, and strengthening, which involves selecting strategic directions at the brand concept level (functional, symbolic, experiential). Approached from this perspective, the company’s image is strengthened in a consequential manner and, as a result, can have a long-lasting impact on the company's competitiveness in the market.

Internal Ballistic Modeling and Simulation Analysis of High-low Pressure Low-overload Launch of Unmanned Aircraft

The low-overload launch is an important research direction in weapon launch. In this paper, a new low-overload launch method is designed by using the piston-type high-low pressure launch principle combined with the secondary launch principle. Based on the classical internal ballistic equations and multi-body dynamics equations, the internal ballistic model of this low overload launch system is established. A joint simulation model based on MATLAB and RecurDyn is constructed to simulate the internal ballistic state during the launch process. The sensitivity of each parameter change of the high-low pressure system to the launch overload is also studied. The results show that the maximum low-pressure chamber pressure of the low overload launcher in this paper is reduced by 62% compared to the conventional internal ballistic pressure, the saturation of the pressure curve is also improved, and the muzzle velocity is accelerated; the maximum overload is reduced by 65%, which can meet the requirements of muzzle initial velocity and low overload when launching unmanned aircraft.

Numerical simulation analysis of the flow field in the bore of a two-stage light gas gun

In order to study the effect of different launch tube diameters of gas-driven two-stage light gas guns on the flow field during the launch process, a model of the piston movement in the pump tube to the projectile launch was established using Fluent. Using the dynamic mesh technology and 6DOF model, a numerical simulation of the projectile launch process of the two-stage light gas gun was carried out, and the effects of different launch tubes on the projectile velocity and the flow field in the bore were obtained. The results show that when the mass difference between the piston and the projectile is large, appropriately increasing the diameter of the launch tube is conducive to the flow of gas in the high-pressure cone and increases the projectile launching speed. The numerical simulation analysis of the flow field in the bore provides a basis for the design and optimization of the two-stage light gas gun.

The turbulent-flow-assisted electrostatic collection and alignment of recycled short-chopped carbon fiber in gaseous phase

Short-chopped carbon fiber is a main recycled product of carbon fiber materials that shows great advantage of anisotropy on mechanical or functional properties; however, their considerable agglomeration leads to limitations of separating and controlling individual fiber’s placement and orientation to fine-tune properties of final composite materials. Here we report a turbulent-flow-assisted electrostatic collection and alignment method that results in exceptional disentanglement efficiency, good collection and launching efficiency with great orientation performance in the gaseous phase. The pneumatic dispersion shows a nearly complete disentanglement efficiency (97 %) at a pressure reduction of 0.5 MPa, which ensures full utilization of electrostatic property for each disentangled fiber. By energization of the dielectric layer at different voltage levels, re-entrainment of conductive carbon fiber was avoided, while the collection and launching efficiency could reach 62 % and 47 %, respectively. By fast-frame imaging, the disentanglement, migration, landing and launching process was studied. The electrostatic polarization for launching leads to free-angle flocking that over 97 % of short fibers were controlled to be aligned within azimuthal angle from 60° to 90° regardless of launching angle. The combined disentanglement and alignment offer an attractive material system for recycling short-chopped carbon fibers and fabricating reinforced or functionalized composite materials.

Ocean observation system design of mooring buoy and benthic node with electro-optical-mechanical cable

We designed a hybrid system named Mooring Buoys Observation System with Benthic Electro-optical-mechanical Cable (MBOSBC) for long-term seafloor and sea surface multi-parameter ocean observation. The electro-optical-mechanical (EOM) cable connects a sea surface buoy and a seafloor junction box so as to establish a transmission link of information and power between the sea surface and the seafloor. The EOM cable also plays the role of mooring tether to the MBOSBC and has to withstand the rigorous marine environment—experiencing mooring loads under complex marine environmental conditions for long periods of time. The data transmission of the system includes the EOM, satellite communication, wireless radio, and acoustic communication. The system power is generated by a wind turbine and solar panels and is transmitted to the seafloor junction box. An acoustic communication instrument is used to gather the sample data from other benthic nodes, such as seafloor landers, AUVs, and underwater gliders. MBOSBC is designed to operate from shallow water to deep sea, and to simultaneously monitor sea surface hydrology, meteorology, and water quality, as well as benthic temperature, pressure, salinity, currents, and seafloor video. We provide the MBOSBC architecture design, including the mechanical design, control, power, data transmission, and EOM cable. Finally, we describe the launch and recovery process of MBOSBC, as well as experimental results.