11 results about "Ship hydrodynamics" patented technology

The application provides a flow field reconstruction and deduction method based on K-A theorem, and belongs to the technical field of ship hydrodynamics. First, multi-dimensional data such as the direction, amplitude, period, frequency and flow velocity of irregular waves are collected and integrated into high-dimensional wave vectors. Then, the KAN network with B-spline curve as a learnable function is used to map the high-dimensional input into a low-dimensional parameter list, obtain the amplitude, angular frequency and initial phase of the dominant equivalent regular wave, calculate the decoupling target function by constructing an equivalent wave superposition model, compare the decoupling target function with the true value to obtain a loss function, and then optimize the network parameters by backward propagation until convergence. Finally, based on the network output parameters, a wave superposition model is constructed to represent the real wave in the form of a series of interpretable regular waves superimposed in time sequence, so that efficient and accurate flow field reconstruction and deduction are realized.

The present application belongs to the field of ship hydrodynamics and motion prediction, and in particular to a device and method for predicting the hydrodynamics and motion of a ship coupled with ice, which first derives a Green function that satisfies the boundary conditions of the ice layer and the free surface, as well as all other conditions except the surface condition of the ship, and through the Green function, the differential equation of the velocity potential is converted into a boundary integral equation on the surface of the ship only, which introduces an extended surface at the waterline of the ship body to eliminate the influence of irregular wave frequencies; an asymptotic solution formula of the Green function is analytically derived, thereby establishing an approximate and effective solution program for the coupled interaction of the ship / wave / ice layer, and numerically calculating the results of the added mass, damping coefficient and wave exciting force of the ship body; through the method, the interaction mechanism of the water wave / ship / ice layer under different parameter characteristics can be deeply understood, and theoretical support is provided for the hydrodynamic problems, motion prediction and rational design of polar ships.

A method for measuring the hydrodynamic pressure of a bilge keel on a surface ship includes: 1. Determining the main structure and bilge keel structure of a ship model, with a scale ratio of λ, and determining the positions of n measurement nodes located on the lower surface of the bilge keel; 2. Modeling the ship model from step 1 and comparing the strain at each measurement node with the strain at the lower surface of the bilge keel by applying water pressure, and calculating the strain transfer coefficients C1 to C2 corresponding to the n measurement nodes. n 3. Construct the boat model from step 1, and conduct a water immersion test in the test tank to obtain the water velocities V1 to V at n measurement nodes. n The micro-strain με1~με at n measurement nodes was measured. n 4. Obtain the hydrodynamic pressure P at the measurement node of the ship model. i :P i =με i / C i , i = 1, 2, 3…n; V. Obtain the actual ship hydrodynamic pressure SP at the corresponding measurement node positions of the bilge keel on the actual ship. i And the actual ship's entry speed SV i SP i =λ×P i This allows us to obtain hydrodynamic pressure data for the bilge keel under different working conditions, which can be used to assist in bilge keel design and improve the reliability of the bilge keel structure.

The application provides a kind of ship quick current environment under the control method of unberthing pilot operation, it is related to marine engineering equipment technical field.The method obtains ship static parameters and actual draught, generates ship hydrodynamic characteristic tensor;Three-dimensional flow velocity vector data, physical cable real-time tension vector, actual heading angle and actual yaw angle rate are obtained, and the stream velocity scalar and the absolute flow direction angle are extracted;Calculate relative drift angle, solve the original longitudinal force, the original transverse hydrodynamic force and the original yaw torque translated to the first back cable support point position;Based on the original yaw torque, the pre-tightening force threshold and the safe working load, the safety interlocking logic is constructed, the asymmetric uncabling timing instruction and the target external rotation angle rate are generated;The deviation between target and actual angle rate is calculated to generate instruction compensation torque, and the transverse fine-tuning thrust is issued according to the longitudinal force arm of the auxiliary tugboat.The application parasitizes the longitudinal flow force as the unberthing external rotation energy, eliminates the risk of quick current cable breaking and reduces the energy consumption of tugboat.

The invention relates to the technical field of ship automatic control, and discloses a propeller rotating speed fault-tolerant control method and system in a navigational speed keeping scene, and the method comprises the steps: synchronously collecting the physical rotating speed of a propeller, the output torque of a main engine, and the real-time navigational speed of a ship; the soft measurement rotating speed is calculated on line based on the navigational speed and ship hydrodynamic parameters; carrying out fusion observation on the two paths of rotating speed signals by utilizing a self-adaptive sliding mode observer, and generating a system state observation value and a lumped disturbance observation value; the hard fault of the sensor is reliably diagnosed based on the logic that the double residuals continuously exceed the threshold value by calculating the physical measurement value and the residual error of the two; after definite diagnosis, smoothly switching a closed-loop feedback signal to a soft measurement value to generate a fault-tolerant arbitration rotating speed; and finally, feedforward and feedback compound control is carried out based on the rotating speed deviation in combination with a disturbance observation value, and a driving instruction is generated. According to the method, the continuous and stable operation of the navigational speed control loop can be maintained when the rotating speed sensor has a hard fault without hardware redundancy.

The application discloses a kind of based on improved model predictive control unmanned ship trajectory tracking control method and device.The method includes, H-PINN method is introduced into unmanned ship hydrodynamics model, obtains the simplified hydrodynamics model of unmanned ship;Based on the prediction model of the trajectory tracking of unmanned ship obtained in simplified hydrodynamics model, the expected trajectory and control quantity of model predictive control MPC are designed using differential flatness theory, and stability analysis is designed according to Lyapunov function.The method improves model predictive control using differential flatness theory, and Lyapunov function optimization analysis is combined, improves trajectory tracking precision, reduces the change amplitude of control quantity, so that the speed change in navigation process is more smooth.

This invention discloses a time-domain numerical method for calculating the hydrodynamic performance of ships in the field of marine hydrodynamics. The method includes: establishing a three-dimensional numerical model of the hull and free surface; decomposing the total velocity potential based on time-domain potential flow theory; constructing boundary integral equations; introducing a time-increasing monotonically increasing function to smooth the initial transient response; simultaneously iteratively solving the free surface evolution and the ship's six-degree-of-freedom motion equations; and achieving self-consistent coupling between flow field pressure and ship motion using a closed feedback loop. This method also supports nonlinear free surface boundary conditions, suppresses numerical dissipation through high-order extrapolation, and dynamically calculates the restoring force matrix based on surface element integrals, significantly improving the calculation accuracy and stability of ship motion response in confined waters. It is suitable for engineering prediction of complex conditions such as near-shore navigation, shallow water resonance, and shoreline reflection.

The application provides a rudder ball thrust fin capable of rotation and release, and belongs to the field of ship hydrodynamic energy-saving devices. The rudder ball thrust fin can solve the problem that the resistance generated by the existing rudder ball thrust fin during the high-speed sailing of a ship can exceed the propulsion benefit, which will lead to the increase of the overall resistance, and thus the energy-saving effect of the rudder ball thrust fin is lost. The rudder ball thrust fin comprises a rudder body, an integrated rudder ball, a thrust fin, an integrated rudder blade, a rudder ball rotating mechanism and a rudder blade rotating mechanism. The integrated rudder ball is provided with the thrust fin on both sides. The integrated rudder ball is rotationally arranged on the rudder body. The rudder body is provided with a thrust fin groove at the upper end and the lower end of the integrated rudder ball. The two thrust fins are respectively embedded in the two thrust fin grooves. The integrated rudder blade is rotationally arranged on the outer side of the thrust fin groove. The rudder ball thrust fin is mainly used for ship hydrodynamic energy-saving devices.

The invention relates to the field of ship hydrodynamics and numerical simulation, and discloses a giant estuary ship navigation capability numerical simulation model test method, which comprises the following steps: executing a prospective preparation step, and constructing a baseline physical model; executing a baseline simulation and dynamic risk assessment step, performing navigation simulation under the driving of the baseline physical model, and calculating a dynamic risk potential field value in real time; when the dynamic risk potential field value exceeds a trigger threshold value, executing a high-fidelity instantiation step, and activating a high-fidelity physical kernel module; an asynchronous coupling calculation step is executed, and the accurate hydrodynamic force calculated by the high-fidelity module is used for replacing a ship body hydrodynamic force item in the baseline ship control model; when the dynamic risk potential field value is continuously below a degradation threshold, a model degradation step is performed, and calculation of its inherent hull hydrodynamic terms by the baseline ship manipulation model is resumed. By means of the dynamic switching mechanism, high-precision computing resources are only input in a necessary high-risk section, and efficient simulation is maintained in a low-risk section.

The application discloses a device suitable for measuring roll excitation moment of a ship model loaded with fluidized cargo in the technical field of ship hydrodynamics test and ship model test technology, and comprises a pool trailer system, a wave generator and a measuring model, wherein the measuring model comprises a ship model, an inner frame and an outer frame, the bow and the stern of the ship model are provided with adjustable connecting devices rigidly connected with the end of the ship body, the adjustable connecting devices comprise flanges, the flanges comprise a bow flange and a stern flange, the bow flange and the stern flange are fixedly connected with the bow and the stern of the ship model respectively, and the bow flange and the stern flange can adjust the relative height thereof with the ship model through sliding grooves; the device further comprises rotating shafts and torque sensors, the rotating shafts comprise a bow rotating shaft and a stern rotating shaft, and the inner side of the inner frame is fixedly provided with the torque sensors at both ends, and the device can accurately measure the roll excitation moment of the ship model loaded with fluidized cargo in the seakeeping test through cooperation of the inner frame and the outer frame.

This invention provides a numerical calculation method and system for inter-ship effects during the lateral replenishment approach phase of two ships based on CFD-MMG coupling, belonging to the field of ship hydrodynamic numerical simulation technology. The method includes: constructing an MMG ship motion mathematical model; acquiring the dynamic response time history data of the ship from start-up to stable navigation; and determining the stable navigation time based on the response convergence criterion; constructing a segmented adjustment strategy based on state event triggering, using propeller speed as the control input; reconstructing unsteady velocity and displacement data segmentally under overall relative displacement constraints, and adjusting the trajectory according to the navigation phase to achieve spatial closed-loop control of the two ships from overtaking to parallel operation; constructing a continuous-time velocity function to drive ship motion based on the segmented reconstruction results, while maintaining physical consistency and continuity; embedding the continuous velocity function into CFD numerical calculation, and using an overlapping grid method to simulate the relative motion of the two ships from overtaking to parallel operation, thereby obtaining the inter-ship hydrodynamic and flow field evolution results.