39 results about "Normal velocity" patented technology

A pressure wavefield and a normal velocity wavefield measured on a smoothly shaped acquisition surface by towed dual-sensor marine seismic streamers are decomposed into up-going and down-going pressure and particle velocity components on an observation level between the acquisition surface and a sea surface of undetermined shape. The up-going and down-going pressure and particle velocity components are extrapolated iteratively in steps from the observation level toward the sea surface. An image point and a reflection coefficient of the sea surface at the image point are determined from the iteratively extrapolated up-going and down-going pressure and particle velocity components.

Embodiments of the present invention relate to methods for calculating the aerodynamic forces and moments on fixed wing aircraft experiencing dynamic ground effects in subsonic flight. An airfoil and its trailing vortices are modeled as a lifting line with trailing vortex sheets and an image lifting line with trailing vortex sheets. The lifting line is located at a certain height above the ground and its image is located at an equal height below the ground, in order to satisfy a boundary condition of zero normal velocity at the ground. A downwash velocity at the airfoil is expressed as the sum of the downwash velocities from the lifting line and its image and is dependent on the height above the ground. The angle of attack of the airfoil is then expressed as a function its downwash velocity, the geometry of the airfoil, and a series representation of its vorticity distribution. The vorticity distribution is calculated from the angle of attack by numerical substitution. Aerodynamic forces and moments on the airfoil are calculated from the vorticity distribution. In another method, a lifting surface and image lifting surface are used to model an airfoil. These methods have particular use in autoland systems, autopilot systems and computer simulations.

The invention discloses an arched groove gas film cooling structure for turbine blades. An arched groove front edge and a rounded groove back edge are arranged at an outlet of a gas film hole, and the structure is formed. The arched groove front edge is obtained through differencing of the bottom of a transverse groove and a quarter of a cylinder arc, and the radius of the cylinder arc is smaller than the groove depth. Smooth transition from the normal velocity of gas flow after the gas flow leaves the gas film hole to the flow-direction velocity is realized effectively by the aid of the arched front edge, and the cold gas loss caused by direct injection of a large quantity of cooling gas flow into a main flow is avoided; and the momentum loss of jet flow is reduced through smooth transition of the velocity of the cooling gas flow, so that the jet flow is better attached to the wall surface. Collisions between the jet flow and the back edge are reduced by the aid of the rounded groove back edge, so that the flow resistance of the cooling gas flow is reduced, the jet flow is divided to two sides more easily, the spanwise covering of the cold gas is increased, meanwhile, the cold gas climbing out of the groove can be closely attached to the position close to the wall surface, protection of the gas film on the downstream wall surface of the groove is formed, and the cooling effect is good.

The invention provides an estimation method of wave force submerging an offshore bridge upper structure. A theory accrual model of the wave action of a bridge upper structure in a submerging state isbuilt based on a potential flow wave theory, a control equation of the model is a Laplace's equation, boundary conditions such as impassable and impermeable characteristics of a free surface and a seabed and zero object plane normal velocity are met, a velocity field can be solved by solving a control equation and by the aid of continuity of velocity potential and horizontal velocity, and the waveaction force can be solved by the aid of a Bernoulli's equation. By a built wave action force computing method, maximum wave action force applied to an offshore bridge structure in the submerging state can be accurately calculated, and accuracy is obviously improved as compared with a previous method.

The invention relates to a drop condensation enhanced heat exchange surface structure with draining hoses. The drop condensation enhanced heat exchange surface structure comprises heat exchange areas and the draining hoses, and the heat exchange areas and the draining hoses are arranged at intervals so as to keep the drop condensation heat exchange process with condensed liquid drops falling off automatically. In the normal working process, the draining hoses on the heat exchange surface structure are perpendicular to the direction of gravity. The heat exchange surface structure is cooled, the temperature of the heat exchange surface structure is kept to be lower than the saturation temperature corresponding to contact gas pressure, and high temperature gas is subjected to drop condensation in the heat exchange areas. As condensation continues, the condensed liquid drops undergo the processes of nucleation, development and combination to be generated continuously and to grow up. Large liquid drops slip down along the surface under the action of gravity, due to the fact that the shapes of the liquid drops are changed suddenly when the liquid drops pass through the draining hoses, the surface energy of the liquid drop part can be converted into kinetic energy, the liquid drops are made to acquire a heat exchange surface normal velocity and to be disengaged from the heat exchange surface completely under the action of the gravity, and the self-disengaging process of the liquid drops is achieved. The drop condensation enhanced heat exchange surface structure with the draining hoses is simple in structure, reliable in working principle and capable of effectively solving the problem that heat exchange capability is weakened obviously due to the failure of the heat exchange areas.

The invention provides an estimation method for a structure low-frequency radiation sound power under a vibration distributed undersampling condition. The method comprises the steps of (1) measuring the geometric size and shape of a structure; (2), distributing a plurality of vibration speed sensors on the structure surface to obtain the normal velocity of a limited point at the structure surface; (3), computing a structural radiation modal and the accompanying coefficient of each order of radiation modal; (4), performing interpolation on the structure surface normal velocity based on the sound radiation modal; (5), obtaining the accompany coefficient of the radiation modal after the interpolation; and (6) estimating the radiation sound power. The method based on the structure sound radiation modal obtains the vibration speed of the structure corner position by interpolation, and can more accurately estimate the sound power, and the interpolation method is not relevant to the physical performances and boundary conditions of the structure.

A laser-beam-scanned optical disc includes an information recording area and an information management area. The information management area stores recording management information having portions corresponding to respective integer multiples of a normal velocity relating to scanning of the disc. Each of the portions of the recording management information contains a first information piece representative of a recording strategy for recording of information on the information recording area and a second information piece representative of a recording laser power for recording of information on the information recording area.

Using a mechanical shaker test the shear wavespeed in a plate is estimated by applying a cyclical point force to the plate, measuring normal velocity of waves caused by the force, transforming temporal domain measurements with a Fourier transform into a frequency domain, transforming spatial domain measurements into a {k_x,k_y} wavevector domain spectra using Fourier transforms, determining propagation wavenumbers for given Lamb waves from peaks within the {k_x,k_y} spectra, and determining shear wavespeed by applying a Newton-Raphson gradient method using the propagation wavenumbers to Raleigh-Lamb dispersion curve equations.

The invention provides a numerical calculation method of mooring damping. The damping contribution of a mooring system as a motion response to a marine floating structure can be accurately calculated.Firstly, a lumped mass method or a nonlinear finite element method is utilized to calculate the motion response of a mooring line under the top forced displacement excitation, and the position and velocity of each micro-segment node of the mooring line are obtained; secondly, the angle, normal velocity and tangential velocity of each micro-segment unit are calculated, and normal and tangential drag forces performed on the mooring line are solved based on a Morison formula; finally, the work of the drag forces performed on each micro-segment of the mooring line within a motion cycle is calculated, integration is conducted along the whole length of the mooring line, the energy consumed by the mooring line within one cycle can be obtained, and therefore an equivalent linearized mooring damping coefficient is obtained. The calculation method of mooring damping is high in precision, meanwhile, not only can the whole damping contribution of the mooring line be evaluated, but also the contribution ratio of any length segment in the mooring line to the whole damping can be studied, and a reference is provided for the design of the mooring system.

The invention relates to an experimental method of capture trajectories. The experimental method includes: acquiring aerodynamic coefficient of an external store without interference of an aerial carrier and aerodynamic coefficient of the external store with interference of the aerial carrier so as to acquire interference value of the aerial carrier; acquiring real attack angle of the external store; according to the real attach angle of the external store, performing interpolation or extrapolation to acquire the aerodynamic coefficient of the external store under the real attack angle; according to the interference value of the aerial carrier and the aerodynamic coefficient of the external store under the real attack angle, acquiring motor parameters of the external store in the next motion position after delta t time, and calculating corresponding aerodynamic parameters by the aid of the motion parameters; repeating the above steps to acquire the entire drop trajectory data of the external store. With the method, added attach angle caused by normal velocity of the external store is considered, relative attitude angles of the external store and the aerial carrier can be guaranteed, and displacement and attitude angles of the external store during dropping can be accurately guaranteed.

The present invention discloses a vehicle navigation method, a system, a device, and a readable storage medium. The method comprises steps of determining whether a GPS satellite signal reaches an effective strength; if not, determining whether a vehicle is moving; if not, establishing a first system according to the state information of the vehicle and conducting zero-velocity correct to assist positioning and navigation of the vehicle; if so, establishing a second system model according to the state information and constraint conditions and conducting zero-velocity correct to assist positioning and navigation of the vehicle; wherein the state information includes position information, speed Information, attitude information, three-dimensional lever arm information, an accelerometer zero-bias error and a gyroscope drift error; the constraint conditions specifically comprise that a lateral velocity and a normal velocity perpendicular to the ground for the vehicle are both zero. The method of the invention obtains the state information without using an additional sensor, and conducts zero-velocity correct without stopping the vehicle when the GPS signal is out of lock for a long time, thereby achieving a reliable and effective positioning and navigation in both motion and stationary states.

The invention relates to an aluminum scrap depositing and melting device, which mainly comprises a main melting chamber, an electromagnetic pump, a charging well and a connecting pipeline, wherein the main melting chamber is connected with the charging well through a feed pipe and the electromagnetic pump arranged on the feed pipe; the charging well is connected with the main melting chamber through a return pipe arranged at the bottom to form a circulation loop; the charging well has a cylindrical bucket body structure; the cross sections of the feed pipe and the return pipe are round; the connecting angle between the feed pipe and the charging well in the vertical direction is between 91 and 93 degrees; and the connecting angle between the return pipe and the charging well is between 91 and 93 degrees. The angle for the feed pipe entering the charging well in the horizontal direction enables the molten aluminum to simultaneously have a tangential velocity and a normal velocity relative to the round cross section of the charging well, the mounting position of the return pipe is favorable for the formation of a vortex, and the size of the pipe diameter ensures the liquid height in the charging well so that the molten aluminum forms the vortex with high vortex strength in the charging well and can quickly entrain and cover the aluminum scraps added into the charging well. The depositing and melting device has high depositing and melting capability and high production efficiency.

The invention relates to an in situ on-line acoustic detection method of velocity field at a deep-sea hydrothermal vent. The traditional hydrothermal vent velocity field detection method can not accurately measure the velocity distribution at a hydrothermal vent. The method comprises the steps of: firstly enabling a underwater transducer No.1 in the lower layer to transmit acoustic signals, and receiving the acoustic signals by all underwater transducers in the upper layer, which are used as receiving underwater transducers, and calculating the transit time of the acoustic wave between the underwater transducer No.1 in the lower layer and all the underwater transducers in the upper layer; secondly, repeating the process to obtain the transit time of the acoustic wave between each underwater transducer in the lower layer and all the underwater transducers in the upper layer; then using the underwater transducers in the upper layer to transmit acoustic wave, using all the underwater transducers in the lower layer to receive the acoustic wave, and calculating the transit time of the acoustic wave between each underwater transducer in the upper layer and all the underwater transducers in the lower layer; and finally rebuilding the two dimension mean normal velocity field at the deep-sea hydrothermal vent by adopting data reduction chromatography. The method adopts a non-contact measuring mode, can perform continuous real time measuring in severe environment, and improves the measuring accuracy of heat flux at the hydrothermal vent.

This invention discloses an optimizing method for the attached mass position of a curve vibration thin plate loudspeaker including: setting up a curve vibration thin plate model based on a PDE module of a FEMLAB software to define its parameter and its border conditions, then carrying out network division to the plate and mode analysis and that of the steady-state to get the mode distribution when the plate is not attached by the mass and the normal velocity of its surface vibration, then combining the inherit optimization algorithm to optimize the mode distribution so as to get the optimum position of different attached masses under rather smooth mode distribution and fixing the attached mass on a related optimum position of the plate to get a better sound pressure frequency response curve and finally getting related sound pressure frequency response curve based on the computation of Rayleigh integral formula.

There is disclosed a disk drive using a disk medium in which a non-servo range exists. In order to position a head at a target track, a CPU executes a seek operation by normal velocity control using servo data. At this positioning, when the head passes the non-servo range from which no servo data can be obtained, the CPU executes a seek operation by special velocity control to move the head at a velocity calculated based on a moving distance of the non-servo range.

The invention discloses a radiation noise prediction method for a naval vessel vibration shell, and the method comprises the steps of collecting a vibration signal of the naval vessel vibration shell; performing time integration on the two tangential acceleration signals and the normal acceleration signal to obtain two tangential speed signals and a normal speed signal; building a naval vessel vibration shell radiation noise prediction model based on sound wave speed and sound pressure control equation space discretization and time integration, wherein sound field variables comprise sound pressure p (x, t), sound wave tangential speed utau '(x, t) and utau' '(x, t) and sound wave normal speed un (x, t), and x represents different positions of a sound radiation field; for sound field variables, constructing a non-reflection prediction model of PML by adopting a DRP spatial discrete format and an LDDRK time integral format; adding a tangential speed variable and a normal speed variable into the model to calculate the change condition of the sound field along with time under the condition of shell vibration; and calculating the influence of the motion of the naval vessel vibration shell on the sound field variable at each time step so as to predict the sound radiation of the naval vessel vibration shell at each moment.

The optical disk recording/reproduction device is provided with an information recording area search means, comprising, a moving means which detects the presence and absence of information and return moves an optical pickup from inward to outward or from outward to inward direction of an optical disk, and a stopping means which stops the movement of optical pickup if an information recording area is detected in the movement of optical pickup. If the existence of information cannot be confirmed at a re-zeroing position in the initial operation, the optical pickup is moved to the inward of optical disk at a normal velocity; when the optical pickup passes through the information recording area, it is braked and stopped. If the existence of information can be confirmed at the stop position, the flow is shifted to normal reproduction; if it cannot be confirmed, the optical pickup is determined to pass through the information recording area and stop, returned from the stop position and moved outward at a low speed. In the outward movement, the moving velocity is switched to the minimum velocity nearby the position of information recording area detected in the first inward movement. Thus, the recording information is surely searched and read in the initial operation even if the optical disk has only extremely small information recorded thereon.

The invention provides a rotating speed control method of a ball mill based on the grinding effect of steel balls in the ball mill, and relates to the field of energy conservation and consumption reduction of efficient development and utilization of solid mineral resources. The rotating speed control method comprises the steps that coordinate systems XAY and xoy are established, and a detachment angle alpha, a fall-back angle beta and included angles theta and gamma of the steel balls are defined; the coordinates of a point B and a point C in the coordinate system XAY and the relationship between the angle alpha and the rotating speed of the mill are determined; the velocity component in the vertical direction of the steel balls at the point B is determined; the final speed of the steel balls at the point B are determined; the sine and cosine of the angle theta are determined; the coordinates of the point B of the steel balls in the coordinate system xoy are determined; the relationship between the angle beta and the angle alpha is determined; the cosine of the angle gamma is determined; the normal velocity of the steel balls falling back to the point B is determined; and a methodfor adjusting and controlling the rotating speed psi of the ball mill is determined. The rotating speed control method realizes the timely adjustment of the rotating speed of the ball mill by means ofa frequency conversion speed regulation technology, so that the working state of the ball mill is adapted to the specific properties of a processing object at any time, and the technical and economicindexes of the ore grinding process are always in the best state.