Method and system for transferring motion energy of large ship in wind wave flow environment

Abstract

The invention provides a method and a system for transferring motion energy of a large ship in a wind wave flow environment, and the method comprises the steps: building a first fluctuating wind speed model based on the feature parameters of sea wind, sea waves and ships under different sea conditions, and calculating the power spectrum density of the fluctuating wind speed through employing a specific calculation method; constructing a relational expression between the power spectrum density and the amplitude of the fluctuating wind speed in the angular frequency interval range; a second fluctuating wind speed model is obtained through the relational expression and the first fluctuating wind speed model, and then the absolute wind speed of the sea wind is calculated; and finally, based on the time domain motion signal and the absolute wind speed in any marine environment, respectively calculating the average power of the sea waves, the sea wind and the ship by adopting a specific calculation method, and further calculating the energy transfer efficiency of the disturbed motion of the ship under different sea conditions. The motion characteristics and the energy transfer relation of the large ship in different working conditions can be comprehensively described by fully considering the working condition environment jointly influenced by complex wind wave and flow environments under different sea conditions.

Description

Technical Field

[0001] The present invention relates to the field of ship engineering and ocean engineering technology, and in particular to a method and system for transmitting motion energy of a large ship in a wind, wave and current environment. Background Art

[0002] With the rapid development of the marine transportation industry, the study of the motion behavior of large ships in complex marine environments and their energy transfer mechanisms is particularly critical. The navigation of ships at sea is not only affected by natural factors such as waves, sea winds and currents, but these factors also determine the motion stability of ships under different sea conditions. Especially for large ships, accurately understanding and predicting their motion characteristics under severe sea conditions is crucial to ensure navigation safety.

[0003] Traditional ship motion analysis methods mainly focus on the calculation of static and dynamic responses. When analyzing the disturbed motion of ships, these methods often do not fully consider the interaction between sea breeze, waves, and currents, as well as the impact of wave distribution in wind, wave and current environments on energy transfer efficiency. They usually evaluate the performance of ships in specific sea conditions by analyzing single motion modes such as heave, roll and pitch. Therefore, there are still certain limitations when dealing with complex sea conditions, and it is impossible to fully reveal the impact of energy transfer efficiency on ship motion characteristics. Summary of the invention

[0004] The present invention aims at the problems that the interaction between sea breeze, waves and currents is not considered in the current research on the motion behavior of large ships in complex marine environments and their energy transfer mechanisms, and the influence of energy transfer efficiency on the motion characteristics of ships cannot be fully revealed. A method for energy transfer of large ship motion in wind, wave and current environments is provided. Based on the characteristic parameters of sea breeze, wave characteristics and motion state parameters of ships under different sea conditions, a pulsating wind speed model is constructed using a specific calculation method to calculate the absolute wind speed, and then the energy transfer efficiency of the disturbed motion of ships under different sea conditions is calculated. By fully considering the mutual influence and action between sea breeze, waves and currents under different sea conditions, the motion amplitude of ships in complex sea conditions can be effectively reduced, which is of great significance for understanding and coping with complex marine environments. The present invention also relates to an energy transfer system for large ship motion in wind, wave and current environments.

[0005] The technical solution of the present invention is as follows:

[0006] A method for transferring motion energy of a large ship in a wind, wave and current environment, characterized by comprising the following steps:

[0007] Parameter acquisition step: acquiring time domain motion signals under different ocean environments, as well as sea breeze characteristic parameters, sea wave characteristic parameters and ship motion state parameters under different sea conditions, wherein the sea breeze characteristic parameters include the circular frequency of the fluctuating wind speed, the average wind speed at sea level, the correlation length of the wind speed fluctuation, and the amplitude, angular frequency and initial phase of each simple harmonic wave of the fluctuating wind speed; the sea wave characteristic parameters include the circular frequency, amplitude, wave number, wave height and unit width of the wave; the ship motion state parameters include the volume, speed and mass of the ship;

[0008] Power spectrum density calculation steps: calculate the average value of the circular frequency of the fluctuating wind speed according to the circular frequency of the fluctuating wind speed, the average wind speed at sea level and the correlation length of the wind speed fluctuation, and calculate the power spectrum density of the fluctuating wind speed according to the average value of the circular frequency of the fluctuating wind speed, the average wind speed at sea level and the correlation length of the wind speed fluctuation;

[0009] The first fluctuating wind speed model and relationship establishment step: establishing the first fluctuating wind speed model based on the amplitude, angular frequency and initial phase of each simple harmonic wave of the fluctuating wind speed; and establishing an angular frequency interval according to the angular frequency and the bandwidth set based on the angular frequency, and when the angular frequency is within the angular frequency interval, constructing a relationship between the power spectrum density and the amplitude of the fluctuating wind speed;

[0010] The steps of calculating the fluctuating wind speed and the absolute wind speed are as follows: based on the relationship between the power spectrum density and the amplitude of the fluctuating wind speed and the first fluctuating wind speed model, a second fluctuating wind speed model is obtained, and then the fluctuating wind speed is calculated; the absolute wind speed of the sea breeze is calculated according to the fluctuating wind speed and the average wind speed at the sea level;

[0011] The steps of establishing the average signal power model are as follows: a first average signal power model is established based on the time domain motion signal and the simulation time in any ocean environment, and the time domain motion signal is converted into a frequency domain motion signal by Fourier transform, and then the Parsval energy equation about the energy of the time domain motion signal and the energy of the frequency domain motion signal is obtained according to the Parsval theorem; a second average signal power model is obtained according to the first average signal power model and the Parsval energy equation, and an expression of the power spectrum density of the frequency domain motion signal is recursively obtained based on the second average signal power model, and a third average signal power model is recursively obtained based on the second average signal power model and the expression of the power density of the frequency domain motion signal;

[0012] The steps for calculating the average power and energy transfer efficiency are as follows: a wave energy model is established based on the wave height and the unit width of the waves, and the average power of the waves is calculated based on the wave energy model and the third average signal power model; a disturbed sea breeze energy model is established based on the absolute wind speed and air density, and the average power of the sea breeze is calculated based on the disturbed sea breeze energy model and the third average signal power model; a ship energy model is established based on the mass, volume and speed of the ship, and the average power of the ship is calculated based on the ship energy model and the third average signal power model; the energy transfer efficiency of the disturbed motion of the ship under different sea conditions is calculated based on the average power of the ship, the average power of the waves and the average power of the sea breeze.

[0013] Preferably, in the step of establishing the first pulsating wind speed model and the relationship, establishing the angular frequency interval according to the angular frequency and the bandwidth set based on the angular frequency includes: using the frequency equal division method to divide the wave spectrum frequency range under multiple different sea conditions into multiple parts, and setting the length of each part as the bandwidth, and establishing the angular frequency interval of each wave spectrum frequency according to the angular frequency and the bandwidth.

[0014] Preferably, in the parameter acquisition step, the time domain motion signals under different ocean environments include the time domain motion signals of sea breeze, the time domain motion signals of ocean waves and the time domain motion signals of ocean currents; the ocean wave characteristic parameters also include wavelength, and the wave number is calculated based on the wavelength.

[0015] Preferably, in the parameter acquisition step, when obtaining the correlation length of wind speed fluctuations, the correlation length of wind speed fluctuations is obtained by statistically analyzing wind speed data at multiple different time points to improve the adaptability of the model to wind speed changes on different time scales.

[0016] A large ship motion energy transfer system in a wind wave current environment, characterized by comprising a parameter acquisition module, a power spectrum density calculation module, a first fluctuating wind speed model and relationship establishment module, a fluctuating wind speed and absolute wind speed calculation module, an average signal power model establishment module and an average power and energy transfer efficiency calculation module connected in sequence,

[0017] The parameter acquisition module acquires time domain motion signals under different ocean environments, as well as sea breeze characteristic parameters, sea wave characteristic parameters and motion state parameters of the ship under different sea conditions. The sea breeze characteristic parameters include the circular frequency of the fluctuating wind speed, the average wind speed at sea level, the correlation length of the wind speed fluctuation, and the amplitude, angular frequency and initial phase of each simple harmonic wave of the fluctuating wind speed; the sea wave characteristic parameters include the circular frequency, amplitude, wave number, wave height and unit width of the wave; the motion state parameters of the ship include the volume, speed and mass of the ship;

[0018] The power spectrum density calculation module calculates the average value of the circular frequency of the fluctuating wind speed according to the circular frequency of the fluctuating wind speed, the average wind speed at sea level and the correlation length of the wind speed fluctuation, and calculates the power spectrum density of the fluctuating wind speed according to the average value of the circular frequency of the fluctuating wind speed, the average wind speed at sea level and the correlation length of the wind speed fluctuation;

[0019] The first fluctuating wind speed model and relationship establishment module establishes the first fluctuating wind speed model based on the amplitude, angular frequency and initial phase of each simple harmonic wave of the fluctuating wind speed; and establishes an angular frequency interval according to the angular frequency and the bandwidth set based on the angular frequency, and when the angular frequency is within the angular frequency interval, constructs a relationship between the power spectrum density and the amplitude of the fluctuating wind speed;

[0020] The fluctuating wind speed and absolute wind speed calculation module obtains a second fluctuating wind speed model based on the relationship between the power spectrum density and amplitude of the fluctuating wind speed and the first fluctuating wind speed model, and then calculates the fluctuating wind speed; and calculates the absolute wind speed of the sea breeze based on the fluctuating wind speed and the average wind speed at sea level;

[0021] The average signal power model establishment module establishes a first average signal power model based on the time domain motion signal and simulation time in any ocean environment, and uses Fourier transform to convert the time domain motion signal into a frequency domain motion signal, and then obtains the Parsval energy equation for the energy of the time domain and frequency domain motion signals according to the Parsval theorem; obtains the second average signal power model according to the first average signal power model and the Parsval energy equation, and recursively obtains the expression of the power spectrum density of the frequency domain motion signal based on the second average signal power model, and then recursively obtains the third average signal power model based on the second average signal power model and the expression of the power density of the frequency domain motion signal;

[0022] The average power and energy transfer efficiency calculation module establishes a wave energy model based on wave height and unit width of waves, and calculates the average power of waves according to the wave energy model and the third average signal power model; establishes a disturbed sea breeze energy model based on absolute wind speed and air density, and calculates the average power of sea breeze according to the disturbed sea breeze energy model and the third average signal power model; then establishes a ship energy model based on the mass, volume and speed of the ship, and calculates the average power of the ship according to the ship energy model and the third average signal power model; and calculates the energy transfer efficiency of the disturbed motion of the ship under different sea conditions according to the average power of the ship, the average power of waves and the average power of sea breeze.

[0023] Preferably, in the first pulsating wind speed model and relationship establishing module, establishing an angular frequency interval according to the angular frequency and the bandwidth set based on the angular frequency includes: using the frequency equal division method to divide the wave spectrum frequency range under multiple different sea conditions into multiple parts, and setting the length of each part as the bandwidth, and establishing the angular frequency interval of each wave spectrum frequency according to the angular frequency and the bandwidth.

[0024] Preferably, the time domain motion signals under different ocean environments include the time domain motion signals of sea breeze, the time domain motion signals of ocean waves and the time domain motion signals of ocean currents; the ocean wave characteristic parameters also include wavelength, and the wave number is calculated based on the wavelength.

[0025] Preferably, in the parameter acquisition module, when acquiring the correlation length of wind speed fluctuation, the correlation length of wind speed fluctuation is obtained by statistically analyzing the wind speed data at multiple different time points to improve the adaptability of the model to wind speed changes on different time scales.

[0026] The beneficial effects of the present invention are:

[0027] The present invention provides a method for transferring energy of large ship motion in a wind-wave-current environment. The method is based on the characteristic parameters of sea breeze and sea waves under different sea conditions, and uses a specific calculation method to calculate the power spectrum density of the fluctuating wind speed, which can effectively reveal the energy distribution of wind speed fluctuations. Then, a first fluctuating wind speed model is established based on the amplitude, angular frequency and initial phase of each simple harmonic wave of the fluctuating wind speed, which can more finely describe the random variation characteristics of the wind speed, capture the details of the wind speed variation, and improve the authenticity and reliability of the model. An angular frequency interval is established according to the angular frequency and the bandwidth set based on the angular frequency. When the angular frequency is within the angular frequency interval, a relationship between the power spectrum density and the amplitude of the fluctuating wind speed is constructed, which can better identify the different frequencies. The contribution of the frequency component to the total wind speed is helpful to identify the main source of disturbance, thereby optimizing the prediction model and intuitively displaying the energy distribution of different frequency components. Finally, based on the time domain motion signal and absolute wind speed in any ocean environment, a specific calculation method is used to calculate the average power of waves, sea breeze and ships respectively, and then the energy transfer efficiency of the disturbed motion of the ship under different sea conditions is calculated. By fully considering the working environment under the influence of complex wind, wave and current environment under different sea conditions, the motion characteristics and energy transfer relationship of heave, roll and pitch of large ships in different working conditions can be more comprehensively described, which can effectively reduce the motion amplitude of the ship in complex sea conditions, which is of great significance for understanding and coping with complex marine environments.

[0028] The present invention also relates to a system for transferring energy for large-scale ship motion in a wind-wave-current environment. The system corresponds to the above-mentioned method for transferring energy for large-scale ship motion in a wind-wave-current environment, and can be understood as a system for realizing the above-mentioned method for transferring energy for large-scale ship motion in a wind-wave-current environment, comprising a parameter acquisition module, a power spectrum density calculation module, a first pulsating wind speed model and a relationship establishment module, a pulsating wind speed and absolute wind speed calculation module, an average signal power model establishment module, and an average power and energy transfer efficiency calculation module connected in sequence. The modules cooperate with each other, based on the characteristic parameters of sea breeze, characteristic parameters of waves, and motion state parameters of the ship under different sea conditions, and using a specific calculation method to construct a pulsating wind speed model to calculate the absolute wind speed, and then calculate the energy transfer efficiency of the disturbed motion of the ship under different sea conditions. By fully considering the mutual influence and action between sea breeze, waves, and currents under different sea conditions, the motion amplitude of the ship in complex sea conditions can be effectively reduced, which is of great significance for understanding and coping with complex marine environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a flow chart of the method for transferring motion energy of a large ship in a wind, wave and current environment of the present invention. DETAILED DESCRIPTION

[0030] The present invention will be described below in conjunction with the accompanying drawings.

[0031] The present invention relates to a method for transferring motion energy of a large ship in a wind, wave and current environment. The flow chart of the method is as follows: Figure 1 As shown, the following steps are included in sequence:

[0032] Parameter acquisition step: obtaining time domain motion signals under different ocean environments (sea breeze, waves and currents), that is, obtaining time domain motion signals of sea breeze, waves and currents respectively, as well as sea breeze characteristic parameters, wave characteristic parameters and ship motion state parameters under different sea conditions, sea breeze characteristic parameters include circular frequency of fluctuating wind speed, average wind speed at sea level, correlation length of wind speed fluctuation, and amplitude, angular frequency and initial phase of each simple harmonic wave of fluctuating wind speed; wave characteristic parameters include circular frequency, amplitude, wave number, wave height and unit width of waves. Ship motion state parameters include volume, speed and mass of the ship. Preferably, the wave characteristic parameters also include wavelength, and the wave number is calculated according to the wavelength, that is, the wave number k and the wavelength λ have the following relationship: k=2π / λ.

[0033] The steps for calculating the power spectral density are as follows: the average value of the circular frequency of the pulsating wind speed is calculated according to the circular frequency of the pulsating wind speed, the average wind speed at sea level and the correlation length of the wind speed fluctuations, and the power spectral density of the pulsating wind speed is calculated according to the average value of the circular frequency of the pulsating wind speed, the average wind speed at sea level and the correlation length of the wind speed fluctuations.

[0034] Specifically, for the fluctuating wind speed of the sea breeze, there is a fluctuating wind speed spectral density function. First, the average value of the fluctuating wind speed circular frequency is calculated based on the circular frequency ω of the fluctuating wind speed, the average wind speed V at sea level, and the correlation length L of the wind speed fluctuation. The power spectrum density of the fluctuating wind speed is calculated based on the average value of the circular frequency of the fluctuating wind speed, the average wind speed at sea level, and the correlation length of the wind speed fluctuation. Here, the Harris wind spectrum is used. The power spectrum density function S of the fluctuating wind speed is u (ω) is expressed as:

[0035]

[0036] Where, ω is the circular frequency of the pulsating wind speed; is the average wind speed at 10 m above sea level; κ is the surface drag coefficient (κ=0.0025); L is the correlation length unit of wind speed fluctuation (L=1200 m), which is used to describe the spatial correlation of wind speed fluctuations, that is, over what distance the wind speed fluctuations are correlated.

[0037] The first pulsating wind speed model and relationship establishment steps are as follows: the first pulsating wind speed model is established based on the amplitude, angular frequency and initial phase of each simple harmonic wave of the pulsating wind speed; and an angular frequency interval is established according to the angular frequency and the bandwidth set based on the angular frequency. When the angular frequency is within the angular frequency interval, a relationship between the power spectrum density and the amplitude of the pulsating wind speed is constructed.

[0038] Specifically, firstly, a first fluctuating wind speed model is established based on the amplitude, angular frequency and initial phase of each simple harmonic wave of the fluctuating wind speed. The first fluctuating wind speed model is expressed as follows:

[0039]

[0040] In the above formula, represents the amplitude of the nth simple harmonic wave of the pulsating wind speed, represents the angular frequency of the nth simple harmonic wave of the fluctuating wind speed at time t, ε n Indicates the initial phase of the nth simple harmonic wave of the pulsating wind speed.

[0041] Then, the angular frequency interval is established according to the angular frequency ω and the bandwidth Δω set based on the angular frequency

[0042] It should be noted that, in theory, the angular frequency interval (also called the wave spectrum frequency range) is [0, +∞], while in actual simulation, different wave spectrum frequency ranges are selected for different sea conditions, as shown in Table 1.

[0043] Table 1

[0044]

[0045] Preferably, the frequency division method is used to divide the frequency range of the wave spectrum under multiple different sea conditions into multiple parts, and the length of each part is set as the bandwidth, and the angular frequency interval of each wave spectrum frequency is established according to the angular frequency and the bandwidth. That is, the frequency division method is used to divide the frequency range of the wave spectrum into N parts, each part is Δω long, and the frequency range of each part is when When (that is, when the angular frequency is within the angular frequency interval), the relationship between the power spectrum density and the amplitude of the fluctuating wind speed is constructed, that is, the amplitude (amplitude) of the fluctuating wind speed and the power spectrum density have the following relationship:

[0046]

[0047] Here, ρ is the density of seawater.

[0048] Calculation steps of fluctuating wind speed and absolute wind speed: based on the relationship between the power spectrum density and amplitude of the fluctuating wind speed and the first fluctuating wind speed model, a second fluctuating wind speed model is obtained to further calculate the fluctuating wind speed; the absolute wind speed of the sea breeze is calculated according to the fluctuating wind speed and the average wind speed at sea level.

[0049] Specifically, firstly based on the relationship between the power spectrum density and amplitude of the fluctuating wind speed and the first fluctuating wind speed model, that is, according to

[0050] Equation 3 and Equation 2 give the second fluctuating wind speed model, as shown below:

[0051]

[0052] According to the second pulsating wind speed model, the pulsating wind speed v can be calculated wind , according to the pulsating wind speed v wind and the average wind speed at sea level Calculate the absolute wind speed V of the sea breeze wind , calculated according to the following formula:

[0053]

[0054] The steps of establishing the average signal power model are as follows: a first average signal power model is established based on the time domain motion signal and simulation time in any ocean environment, and the time domain motion signal is converted into a frequency domain motion signal by Fourier transform, and then the Parsval energy equation about the energy of the time domain motion signal and the energy of the frequency domain motion signal is obtained according to the Parsval theorem; a second average signal power model is obtained according to the first average signal power model and the Parsval energy equation, and an expression of the power spectrum density of the frequency domain motion signal is recursively obtained based on the second average signal power model, and then a third average signal power model is recursively obtained based on the second average signal power model and the expression of the power density of the frequency domain motion signal.

[0055] To analyze the motion of large ships in complex ocean environments from an energy perspective, we can first calculate the average power of the ocean environment and the ship motion within a limited simulation time to study the energy transfer during the ship motion. Specifically, we first establish a first average signal power model based on the time domain motion signal in any ocean environment (including the time domain motion signal of sea breeze, the time domain motion signal of waves, and the time domain motion signal of ocean currents) and the simulation time. That is, for any time domain motion signal f(t), the first average signal power model P can be defined as:

[0056]

[0057] Wherein, T is the simulation time, which indicates the duration of the time domain motion signal.

[0058] Fourier transform is used to convert the time domain motion signal f(t) into the frequency domain motion signal F(jω), that is:

[0059]

[0060] According to the Pasval theorem, the Pasval energy equation for the energy of the time domain motion signal and the energy of the frequency domain motion signal is obtained. That is, the Pasval energy equation can be used to obtain the equal relationship between the energy of the signal in the time domain and the frequency domain, as shown in the following formula:

[0061]

[0062] Then, according to the first average signal power model and the Parsval energy equation (i.e., according to equations 5 and 7), the second average signal power model is obtained, as shown in the following equation:

[0063]

[0064] Based on the second average signal power model, the expression of the power spectrum density of the frequency domain motion signal is recursively obtained. The power spectrum density of the frequency domain motion signal is defined as:

[0065]

[0066] Finally, the third average signal power model is obtained recursively based on the second average signal power model and the expression of frequency domain motion signal power density, as shown in the following formula:

[0067]

[0068] The signal energy is represented by the average signal power P of the data. Therefore, the energy of the disturbed motion of the ship in the wind, wave and current environment can be calculated through the disturbed motion of the ship, and the relationship between the energy of the marine environment and the disturbed energy of the ship in this process can be analyzed.

[0069] The steps for calculating the average power and energy transfer efficiency are as follows: a wave energy model is established based on the wave height and the unit width of the waves, and the average power of the waves is calculated based on the wave energy model and the third average signal power model; a disturbed sea breeze energy model is established based on the absolute wind speed and air density, and the average power of the sea breeze is calculated based on the disturbed sea breeze energy model and the third average signal power model; a ship energy model is established based on the mass, volume and speed of the ship, and the average power of the ship is calculated based on the ship energy model and the third average signal power model; the energy transfer efficiency of the disturbed motion of the ship is calculated based on the average power of the ship, the average power of the waves and the average power of the sea breeze.

[0070] Specifically, when the surface tension of the ocean wave is ignored, the total energy of the wave within one wavelength per unit width is:

[0071] E wave =0.5ρ w gλ∫ζ 2 (t)dt (11)

[0072] Among them, ρ w represents the density of water, g represents the acceleration due to gravity, ζ represents the wave height, and λ represents the wavelength.

[0073] Therefore, the wave energy model E is established based on the wave height and the unit width of the wave. wave (Also called wave unit micro-element energy E wave ), and the average power P of the waves is calculated based on the wave energy model and the third average signal power model wave , wave energy model E wave and the average power of the waves P wave They are shown as follows:

[0074]

[0075] Where b is the unit width of the wave, S ζ (ω) represents the power spectrum density of the frequency domain motion signal of the wave, which can be calculated by formula (9).

[0076] Then, the disturbance sea breeze energy model E is established based on the absolute wind speed and air density. wind (also known as the unit microelement energy of the disturbed sea breeze), and the average power P of the sea breeze is calculated based on the disturbed sea breeze energy model and the third average signal power model wind , Sea Breeze Energy Model E wind and the average power of the sea breeze P wind They are shown as follows:

[0077]

[0078] In the above formula, V wind is the absolute wind speed, ρ a is the air density, T is the simulation time, and represents the duration of the time domain motion signal.

[0079] Then, the ship energy model E is established based on the ship's mass, volume and speed. ship (It can also be called the unit micro-element energy E of the ship's disturbed motion ship ), and the average power P of the ship is calculated based on the ship energy model and the third average signal power model ship , energy model E ship and the average power of the ship P ship They are shown as follows:

[0080]

[0081] in, is the volume of the ship, L, B, H are the length, width and depth of the ship respectively, m is the mass of the ship, v is the speed of the ship, i is the six degrees of freedom, namely surge, sway, heave, pitch, roll and bow pitch.

[0082] Finally, the energy transfer efficiency of the ship's disturbed motion under different sea conditions is calculated based on the average power of the ship, the average power of the waves, and the average power of the sea breeze, according to the following formula:

[0083]

[0084] After calculating the energy transfer efficiency of the ship's disturbed motion under different sea conditions, a Nimitz-type ship was selected to conduct a simulation test of its energy transfer efficiency changing with the sea state level in the complex wind, wave and current environment of sea conditions from level 1 to 8 set in the study. The test results show that at zero speed, as the sea state level increases, the energy transfer efficiency of the ship's disturbed motion continues to increase, among which the energy transfer efficiency of heave in sea condition level 8 is the largest, the energy transfer efficiency of roll in sea condition level 8 is the largest, and the energy transfer efficiency of pitch in sea condition level 7 is the largest.

[0085] The present invention also relates to a large ship motion energy transfer system in a wind wave current environment. The system corresponds to the large ship motion energy transfer method in the wind wave current environment, and can be understood as a system for implementing the above method. The system includes a parameter acquisition module, a power spectrum density calculation module, a first fluctuating wind speed model and relationship establishment module, a fluctuating wind speed and absolute wind speed calculation module, an average signal power model establishment module, and an average power and energy transfer efficiency calculation module connected in sequence. Specifically,

[0086] The parameter acquisition module acquires time domain motion signals under different ocean environments, as well as sea breeze characteristic parameters, sea wave characteristic parameters and motion state parameters of the ship under different sea conditions. The sea breeze characteristic parameters include the circular frequency of the fluctuating wind speed, the average wind speed at sea level, the correlation length of the wind speed fluctuation, and the amplitude, angular frequency and initial phase of each simple harmonic wave of the fluctuating wind speed; the sea wave characteristic parameters include the circular frequency, amplitude, wave number, wave height and unit width of the wave; the motion state parameters of the ship include the volume, speed and mass of the ship;

[0087] The power spectrum density calculation module calculates the average value of the circular frequency of the fluctuating wind speed according to the circular frequency of the fluctuating wind speed, the average wind speed at sea level and the correlation length of the wind speed fluctuation, and calculates the power spectrum density of the fluctuating wind speed according to the average value of the circular frequency of the fluctuating wind speed, the average wind speed at sea level and the correlation length of the wind speed fluctuation;

[0088] The first fluctuating wind speed model and relationship establishment module establishes the first fluctuating wind speed model based on the amplitude, angular frequency and initial phase of each simple harmonic wave of the fluctuating wind speed; and establishes an angular frequency interval according to the angular frequency and the bandwidth set based on the angular frequency, and when the angular frequency is within the angular frequency interval, constructs a relationship between the power spectrum density and the amplitude of the fluctuating wind speed;

[0089] The fluctuating wind speed and absolute wind speed calculation module obtains a second fluctuating wind speed model based on the relationship between the power spectrum density and amplitude of the fluctuating wind speed and the first fluctuating wind speed model, and then calculates the fluctuating wind speed; and calculates the absolute wind speed of the sea breeze based on the fluctuating wind speed and the average wind speed at sea level;

[0090] The average signal power model establishment module establishes a first average signal power model based on the time domain motion signal and simulation time in any ocean environment, and uses Fourier transform to convert the time domain motion signal into a frequency domain motion signal, and then obtains the Parsval energy equation about the energy of the time domain motion signal and the energy of the frequency domain motion signal according to the Parsval theorem; obtains the second average signal power model according to the first average signal power model and the Parsval energy equation, and recursively obtains the expression of the power spectrum density of the frequency domain motion signal based on the second average signal power model, and then recursively obtains the third average signal power model based on the second average signal power model and the expression of the power density of the frequency domain motion signal;

[0091] The average power and energy transfer efficiency calculation module establishes a wave energy model based on wave height and unit width of waves, and calculates the average power of waves according to the wave energy model and the third average signal power model; establishes a disturbed sea breeze energy model based on absolute wind speed and air density, and calculates the average power of sea breeze according to the disturbed sea breeze energy model and the third average signal power model; then establishes a ship energy model based on the mass, volume and speed of the ship, and calculates the average power of the ship according to the ship energy model and the third average signal power model; and calculates the energy transfer efficiency of the disturbed motion of the ship under different sea conditions according to the average power of the ship, the average power of waves and the average power of sea breeze.

[0092] Preferably, in the first pulsating wind speed model and relationship establishment module, establishing an angular frequency interval according to the angular frequency and the bandwidth set based on the angular frequency includes: using the frequency equal division method to divide the wave spectrum frequency range under multiple different sea conditions into multiple parts, and setting the length of each part as the bandwidth, and establishing the angular frequency interval of each wave spectrum frequency according to the angular frequency and the bandwidth.

[0093] Preferably, the time domain motion signals under different ocean environments include the time domain motion signals of sea breeze, the time domain motion signals of ocean waves and the time domain motion signals of ocean currents; the ocean wave characteristic parameters also include wavelength, and the wave number is calculated based on the wavelength.

[0094] Preferably, in the parameter acquisition module, when obtaining the correlation length of wind speed fluctuation, the correlation length of wind speed fluctuation is obtained by statistically analyzing the wind speed data at multiple different time points to improve the adaptability of the model to wind speed changes on different time scales.

[0095] The present invention provides an objective and scientific method and system for transferring energy of large ship motion in a wind, wave and current environment. The method and system are based on the characteristic parameters of sea breeze, wave characteristics and motion state parameters of the ship under different sea conditions, and adopt a specific calculation method to construct a pulsating wind speed model to calculate the absolute wind speed, and then calculate the energy transfer efficiency of the disturbed motion of the ship under different sea conditions. By fully considering the mutual influence and action between sea breeze, waves and currents under different sea conditions, the motion amplitude of the ship in complex sea conditions can be effectively reduced, which is of great significance for understanding and coping with complex marine environments.

[0096] It should be noted that the above-described specific implementations can enable those skilled in the art to more fully understand the invention, but do not limit the invention in any way. Therefore, although this specification has described the invention in detail with reference to the drawings and embodiments, those skilled in the art should understand that the invention can still be modified or replaced by equivalents. In short, all technical solutions and improvements that do not deviate from the spirit and scope of the invention should be included in the protection scope of the patent for the invention.

Claims

1. A method for transferring motion energy of a large ship in a wind, wave and current environment, characterized in that: The following steps are involved: Parameter acquisition step: acquiring time domain motion signals under different ocean environments, as well as sea breeze characteristic parameters, sea wave characteristic parameters and ship motion state parameters under different sea conditions, wherein the sea breeze characteristic parameters include the circular frequency of the fluctuating wind speed, the average wind speed at sea level, the correlation length of the wind speed fluctuation, and the amplitude, angular frequency and initial phase of each simple harmonic wave of the fluctuating wind speed; the sea wave characteristic parameters include the circular frequency, amplitude, wave number, wave height and unit width of the wave; the ship motion state parameters include the volume, speed and mass of the ship; Power spectrum density calculation steps: calculate the average value of the circular frequency of the fluctuating wind speed according to the circular frequency of the fluctuating wind speed, the average wind speed at sea level and the correlation length of the wind speed fluctuation, and calculate the power spectrum density of the fluctuating wind speed according to the average value of the circular frequency of the fluctuating wind speed, the average wind speed at sea level and the correlation length of the wind speed fluctuation; The first fluctuating wind speed model and relationship establishment step: establishing the first fluctuating wind speed model based on the amplitude, angular frequency and initial phase of each simple harmonic wave of the fluctuating wind speed; and establishing an angular frequency interval according to the angular frequency and the bandwidth set based on the angular frequency, and when the angular frequency is within the angular frequency interval, constructing a relationship between the power spectrum density and the amplitude of the fluctuating wind speed; The steps of calculating the fluctuating wind speed and the absolute wind speed are as follows: based on the relationship between the power spectrum density and the amplitude of the fluctuating wind speed and the first fluctuating wind speed model, a second fluctuating wind speed model is obtained, and then the fluctuating wind speed is calculated; the absolute wind speed of the sea breeze is calculated according to the fluctuating wind speed and the average wind speed at the sea level; The steps of establishing the average signal power model are as follows: a first average signal power model is established based on the time domain motion signal and the simulation time in any ocean environment, and the time domain motion signal is converted into a frequency domain motion signal by Fourier transform, and then the Parsval energy equation about the energy of the time domain motion signal and the energy of the frequency domain motion signal is obtained according to the Parsval theorem; a second average signal power model is obtained according to the first average signal power model and the Parsval energy equation, and an expression of the power spectrum density of the frequency domain motion signal is recursively obtained based on the second average signal power model, and a third average signal power model is recursively obtained based on the second average signal power model and the expression of the power density of the frequency domain motion signal; The steps for calculating the average power and energy transfer efficiency are as follows: a wave energy model is established based on the wave height and the unit width of the waves, and the average power of the waves is calculated based on the wave energy model and the third average signal power model; a disturbed sea breeze energy model is established based on the absolute wind speed and air density, and the average power of the sea breeze is calculated based on the disturbed sea breeze energy model and the third average signal power model; a ship energy model is established based on the mass, volume and speed of the ship, and the average power of the ship is calculated based on the ship energy model and the third average signal power model; the energy transfer efficiency of the disturbed motion of the ship under different sea conditions is calculated based on the average power of the ship, the average power of the waves and the average power of the sea breeze.

2. The method for transferring motion energy of a large ship in a wind, wave and current environment according to claim 1, characterized in that: In the step of establishing the first pulsating wind speed model and the relationship, establishing the angular frequency interval according to the angular frequency and the bandwidth set based on the angular frequency includes: using the frequency equal division method to divide the wave spectrum frequency range under multiple different sea conditions into multiple parts, and setting the length of each part as the bandwidth, and establishing the angular frequency interval of each wave spectrum frequency according to the angular frequency and the bandwidth.

3. The method for transferring motion energy of a large ship in a wind, wave and current environment according to claim 1, characterized in that: In the parameter acquisition step, the time domain motion signals under different ocean environments include the time domain motion signals of sea breeze, the time domain motion signals of ocean waves and the time domain motion signals of ocean currents; the ocean wave characteristic parameters also include wavelength, and the wave number is calculated based on the wavelength.

4. The method for transferring motion energy of a large ship in a wind, wave and current environment according to claim 1, characterized in that: In the parameter acquisition step, when obtaining the correlation length of wind speed fluctuation, the correlation length of wind speed fluctuation is obtained by statistically analyzing the wind speed data at multiple different time points to improve the adaptability of the model to wind speed changes on different time scales.

5. A large ship motion energy transfer system in a wind, wave and current environment, characterized in that: It includes a parameter acquisition module, a power spectrum density calculation module, a first pulsating wind speed model and relationship establishment module, a pulsating wind speed and absolute wind speed calculation module, an average signal power model establishment module and an average power and energy transfer efficiency calculation module connected in sequence. The parameter acquisition module acquires time domain motion signals under different ocean environments, as well as sea breeze characteristic parameters, sea wave characteristic parameters and motion state parameters of the ship under different sea conditions. The sea breeze characteristic parameters include the circular frequency of the fluctuating wind speed, the average wind speed at sea level, the correlation length of the wind speed fluctuation, and the amplitude, angular frequency and initial phase of each simple harmonic wave of the fluctuating wind speed; the sea wave characteristic parameters include the circular frequency, amplitude, wave number, wave height and unit width of the wave; the motion state parameters of the ship include the volume, speed and mass of the ship; The power spectrum density calculation module calculates the average value of the circular frequency of the fluctuating wind speed according to the circular frequency of the fluctuating wind speed, the average wind speed at sea level and the correlation length of the wind speed fluctuation, and calculates the power spectrum density of the fluctuating wind speed according to the average value of the circular frequency of the fluctuating wind speed, the average wind speed at sea level and the correlation length of the wind speed fluctuation; The first fluctuating wind speed model and relationship establishment module establishes the first fluctuating wind speed model based on the amplitude, angular frequency and initial phase of each simple harmonic wave of the fluctuating wind speed; and establishes an angular frequency interval according to the angular frequency and the bandwidth set based on the angular frequency, and when the angular frequency is within the angular frequency interval, constructs a relationship between the power spectrum density and the amplitude of the fluctuating wind speed; The fluctuating wind speed and absolute wind speed calculation module obtains a second fluctuating wind speed model based on the relationship between the power spectrum density and amplitude of the fluctuating wind speed and the first fluctuating wind speed model, and then calculates the fluctuating wind speed; and calculates the absolute wind speed of the sea breeze based on the fluctuating wind speed and the average wind speed at sea level; The average signal power model establishment module establishes a first average signal power model based on the time domain motion signal and simulation time in any ocean environment, and uses Fourier transform to convert the time domain motion signal into a frequency domain motion signal, and then obtains the Parsval energy equation for the energy of the time domain and frequency domain motion signals according to the Parsval theorem; obtains the second average signal power model according to the first average signal power model and the Parsval energy equation, and recursively obtains the expression of the power spectrum density of the frequency domain motion signal based on the second average signal power model, and then recursively obtains the third average signal power model based on the second average signal power model and the expression of the power density of the frequency domain motion signal; The average power and energy transfer efficiency calculation module establishes a wave energy model based on wave height and unit width of waves, and calculates the average power of waves according to the wave energy model and the third average signal power model; establishes a disturbed sea breeze energy model based on absolute wind speed and air density, and calculates the average power of sea breeze according to the disturbed sea breeze energy model and the third average signal power model; then establishes a ship energy model based on the mass, volume and speed of the ship, and calculates the average power of the ship according to the ship energy model and the third average signal power model; and calculates the energy transfer efficiency of the disturbed motion of the ship under different sea conditions according to the average power of the ship, the average power of waves and the average power of sea breeze.

6. The large ship motion energy transfer system in wind, wave and current environment according to claim 5, characterized in that: In the first pulsating wind speed model and relationship establishment module, establishing an angular frequency interval according to the angular frequency and the bandwidth set based on the angular frequency includes: using the frequency equal division method to divide the wave spectrum frequency range under multiple different sea conditions into multiple parts, and setting the length of each part as the bandwidth, and establishing the angular frequency interval of each wave spectrum frequency according to the angular frequency and the bandwidth.

7. The large ship motion energy transfer system in wind, wave and current environment according to claim 5, characterized in that: The time domain motion signals under different ocean environments include the time domain motion signals of sea breeze, the time domain motion signals of ocean waves and the time domain motion signals of ocean currents; the ocean wave characteristic parameters also include wavelength, and the wave number is calculated based on the wavelength.

8. The large ship motion energy transfer system in wind, wave and current environment according to claim 5, characterized in that: In the parameter acquisition module, when acquiring the correlation length of wind speed fluctuation, the correlation length of wind speed fluctuation is obtained by statistically analyzing the wind speed data at multiple different time points to improve the adaptability of the model to wind speed changes on different time scales.

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