110 results about "Drag coefficient" patented technology

The invention provides an aircraft aerodynamic configuration design method and device based on simulation, and relates to the technical field of aircraft aerodynamic configuration design, and the method comprises the steps: obtaining aerodynamic characteristic parameters of aircrafts of different airfoils to construct a multi-source aerodynamic database; a neural network model is established based on the database, airfoil geometric parameters serve as input, the lift coefficient, the resistance coefficient and the lift-drag ratio serve as labels for training, and an aerodynamic performance prediction model is obtained; candidate combinations are generated in an airfoil geometric parameter design space, aerodynamic characteristics of the candidate combinations are predicted through a model, a fitness function is optimized by utilizing dynamic weights, and the combination with the highest fitness is selected as an optimized airfoil parameter by adopting a genetic algorithm; and performing simulation verification on the optimization parameters, extracting a simulation result, comparing the simulation result with the output of the prediction model, judging that the optimization combination is effective when an error meets a preset requirement, and completing aerodynamic configuration design accordingly. The method improves the prediction accuracy and design efficiency of aerodynamic performance.

The invention relates to the technical field of ship design optimization, and discloses a hull shape optimization method based on neural network modeling. In the data acquisition stage of the method, initial appearance parameters and hydrodynamic performance data of a ship body are obtained, the appearance parameters comprise geometric dimensions and shape features, and the performance data comprise resistance coefficients and wave-making resistance values. In the neural network construction stage, a neural network model with a multi-layer perceptron structure is trained by using collected data, weights are updated through a back propagation algorithm, and a nonlinear mapping relation between appearance parameters and hydrodynamic performance indexes is established. In the shape optimization stage, the trained neural network model is used for carrying out iterative adjustment on the shape of the ship body, fluid dynamic performance indexes are recalculated through the model after each adjustment until preset convergence conditions are met, and finally optimized ship body shape data are output. According to the method, partial complex calculation is replaced by the neural network, and intelligent optimization of the hull appearance is realized.

A golf ball is disclosed herein that has at least one modified aerodynamic characteristic or performance trait. More specifically, the golf ball disclosed herein can include a dimple pattern having a specific drag coefficient and / or specific integrated drag area.

A golf ball is disclosed herein that has at least one modified aerodynamic characteristic or performance trait. More specifically, the golf ball disclosed herein can include a dimple pattern having a specific drag coefficient and / or specific integrated drag area.

A golf ball is disclosed herein that has at least one modified aerodynamic characteristic or performance trait. More specifically, the golf ball disclosed herein can include a dimple pattern having a specific drag coefficient and / or specific integrated drag area.

A golf ball is disclosed herein that has at least one modified aerodynamic characteristic or performance trait. More specifically, the golf ball disclosed herein can include a dimple pattern having a specific drag coefficient and / or specific integrated drag area.

A golf ball is disclosed herein that has at least one modified aerodynamic characteristic or performance trait. More specifically, the golf ball disclosed herein can include a dimple pattern having a specific drag coefficient and / or specific integrated drag area.

A golf ball is disclosed herein that has at least one modified aerodynamic characteristic or performance trait. More specifically, the golf ball disclosed herein can include a dimple pattern having a specific drag coefficient and / or specific integrated drag area.

A golf ball is disclosed herein that has at least one modified aerodynamic characteristic or performance trait. More specifically, the golf ball disclosed herein can include a dimple pattern having a specific drag coefficient and / or specific integrated drag area.

A golf ball is disclosed herein that has at least one modified aerodynamic characteristic or performance trait. More specifically, the golf ball disclosed herein can include a dimple pattern having a specific drag coefficient and / or specific integrated drag area.

A golf ball is disclosed herein that has at least one modified aerodynamic characteristic or performance trait. More specifically, the golf ball disclosed herein can include a dimple pattern having a specific drag coefficient and / or specific integrated drag area.

The invention discloses a method and a system for rapidly evaluating aerodynamic performance of an automobile body appearance. The method specifically comprises the following steps: generating a geometric curved surface sample of an automobile body surface by adopting a parameterized design method; carrying out fluid numerical analysis on a vehicle body external flow field; an encoder for vehicle body appearance surface geometry is established, and the geometric structure of the vehicle body surface is recognized; establishing a prediction model based on a multi-scale map neural network, and performing geometric data memory, transmission and updating on the flow field of the vehicle body appearance surface; and outputting vehicle body aerodynamic characteristic parameters (a resistance coefficient, a lift coefficient and a lateral force coefficient) and an error level. Compared with the prior art, the neural network algorithm is ingeniously designed, rapid prediction of the aerodynamic characteristic parameters of the automobile body is achieved, the method can be used for rapid performance evaluation in the automobile body development process, the design efficiency is improved, and the development cost is reduced.

The invention discloses an excavator heat balance performance prediction method, system and device and a storage medium. The method comprises the steps that a heat balance performance test of a standard excavation working condition is conducted; respectively establishing an engine heat dissipating capacity Qw calculation model and an engine air inflow mair calculation model; obtaining Qw and mair under the standard excavation working condition; building a one-dimensional cooling system model; cabin resistance coefficient calibration is completed; setting the heat dissipation power of the hydraulic system, calculating the real-time oil temperature of the hydraulic oil tank based on the one-dimensional cooling system model, adjusting the heat dissipation power of the hydraulic system to enable the difference value between the real-time oil temperature of the hydraulic oil tank and the oil temperature of the hydraulic oil tank to be smaller than a set value, and calculating the ratio b of the heat dissipation power of the hydraulic system to the engine power; and on the basis of a calculation model of Qw and mair, b and the calibrated cabin resistance coefficient, predicting the heat balance performance of the excavator under the target working condition. According to the method, the design accuracy and economy can be improved, the prediction of the full-working-condition heat balance performance is realized, and the high-temperature fault solving efficiency is accelerated.

The invention discloses a ship air sail navigation aiding energy efficiency dynamic optimization method and system and a ship, and relates to the technical field of ship energy conservation. Dynamic parameters in the ship navigation process are collected in real time; establishing a dynamic coupling model; the coupling model is utilized to quantify the dynamic interference of the hull attitude parameters on the air sail state parameters into attack angle offset; a reinforcement learning algorithm is adopted to simulate the attack angle offset, and the optimal attack angle of the air sail is obtained; according to the optimal attack angle and the environmental parameters, target adjustment parameters of the air sail are calculated; and driving the air sail to adjust the sail body rotation angle and the sail surface inclination angle in real time according to the target adjustment parameters. According to the method, the air sails always work in the efficient interval with the maximum lift coefficient and the minimum resistance coefficient, the pneumatic interference model is introduced, the total auxiliary thrust of the multiple sails is improved, the problem that the energy-saving effect is reduced due to dynamic deviation of the attack angle is effectively solved, and the situation that the fuel consumption of a main engine is reduced is stably achieved.

A golf ball is disclosed herein that has at least one modified aerodynamic characteristic or performance trait. More specifically, the golf ball disclosed herein can include a dimple pattern having a specific drag coefficient and / or specific integrated drag area.

A golf ball is disclosed herein that has at least one modified aerodynamic characteristic or performance trait. More specifically, the golf ball disclosed herein can include a dimple pattern having a specific drag coefficient and / or specific integrated drag area.

The application discloses a solid droplet-based drag reduction ball preparation and testing method, and relates to the underwater drag reduction technical field.The preparation method comprises the following steps: performing decontamination treatment on the surface of a steel ball, configuring a PDMS solution and pouring the PDMS solution into a polytetrafluoroethylene mold with small holes with different curvature radii, performing vacuum degassing and solidification, and then peeling off to obtain solid droplet structures with different curvature radii, and bonding the solid droplet structures to the bottom of the steel ball.Through the regulation and control of the solid droplet curvature radius (2.5-10.8 mm) and the water entry speed, the high-speed camera technology is used to observe the change law of the sputtering crown formation, air entrainment and air cavity closure mode in the water entry process, the quantitative analysis of the underwater air cavity volume and the drag coefficient is combined, and the influence of the solid droplet curvature radius on the air cavity shape and the drag reduction performance is verified.The solid droplet structure optimizes the air film capture efficiency, significantly reduces the blunt body pressure difference resistance and the friction resistance, and the preparation process is simple, stable and suitable for the development of the underwater vehicle drag reduction technology.

The application discloses an online identification method for drag coefficient of an interceptor based on artificial intelligence, which utilizes sensors on an aircraft to measure kinematic information of the aircraft and the interceptor in real time, inputs the measured information into an identification model, and obtains the drag coefficient of the interceptor. The online identification method for the drag coefficient of the interceptor based on artificial intelligence has faster identification speed and higher accuracy.

The invention discloses a satellite orbit forecasting method based on in-orbit calibration of model parameters. Belongs to the technical field of remote sensing satellite measurement, operation and control and particularly relates to the technical field of remote sensing satellite orbit forecasting. According to the method, the satellite windward side-to-mass ratio in an atmospheric resistance model is calibrated regularly according to actually measured orbit data, the resistance coefficient in the atmospheric resistance model is calibrated in real time, and more accurate model parameters are used for modeling a perturbative force model in the satellite orbit forecasting process, so that the error of the atmospheric resistance model is reduced, and the orbit forecasting precision is improved. In the time period that the space weather changes gently, the atmospheric resistance modeling precision is improved to 90% or above from about 60%-80% of a traditional method through the method.

The invention discloses an aerodynamic characteristic correction method for a wind turbine airfoil wind tunnel test in the field of wind turbine airfoil aerodynamic characteristic optimization. The method comprises the following steps: 1) constructing a wind turbine airfoil aerodynamic test platform for the wind tunnel test; 2) carrying out safety check on equipment and an experimental environment; (3) measuring the surface pressure of the wind turbine airfoil under the expected working condition by using a high-frequency pressure sensor to obtain a measured pressure signal; 4) performing frequency domain analysis on the pressure signal to obtain the power spectrum density of the pressure signal of the wind turbine airfoil under the expected working condition; 5) estimating and identifying vortex shedding frequency; (6) pressure signal pulsation and measurement errors caused by the vortex are distinguished, a Kalman filter is designed to filter the pressure signals, and corrected pressure signals are obtained; 7) estimating a pressure signal of a specific pressure measuring point position; and 8) calculating to obtain the lift coefficient and the resistance coefficient of the corrected wind turbine airfoil. According to the method, the vortex shedding frequency can be accurately identified, the noise can be effectively filtered, and the correction method of the real aerodynamic coefficient can be obtained.

This invention discloses a method for calculating the fuel consumption saving rate of a vehicle platoon based on topology and dynamic characteristics. The method includes establishing a vehicle dynamics model, an external flow field model, and a mathematical analysis model of the fuel consumption saving rate of the vehicle platoon. The proposed method conducts simulation experiments for different parameters such as longitudinal vehicle spacing, lateral vehicle offset distance, and vehicle speed. By analyzing the influence of longitudinal vehicle spacing, lateral vehicle offset distance, and vehicle speed on the vehicle's aerodynamic drag coefficient, the functional relationship between the vehicle platoon's aerodynamic drag coefficient and the above parameters is determined. Furthermore, the functional relationship between the aerodynamic drag coefficient and the fuel consumption saving rate is determined to calculate the vehicle platoon's fuel consumption saving rate.

The invention discloses a shape-preserving and resistance-reducing design method for a rotating mechanism under rotor / fuselage coupling, which comprises the following steps of: setting the slenderness ratio of a streamline shaft sleeve based on a shape resistance coefficient formula, and verifying the surface pressure distribution and the separation area of the shaft sleeve through numerical simulation to ensure that the shape resistance coefficient meets a resistance-reducing target; setting the area ratio of an outlet to an inlet of the seam based on a Venturi effect formula, so that a low-pressure area is formed in the seam to suck a wing root boundary layer and delay airflow separation; establishing an aerodynamic load and motion parameter coupling model based on an instantaneous resistance formula, analyzing flow fields under different rotation angular velocities and oblique angles through numerical simulation, and optimizing a rotation track to reduce a resistance peak value and aerodynamic torque fluctuation; the invention aims to solve the problems of airflow vortex interference, large shape resistance, high resistance peak and poor aerodynamic stability by optimizing the shape of the rotating shaft sleeve, the fuselage-wing gap structure and the wing rotating track, and improves the cruise fuel efficiency and flight stability of the aircraft.

This invention relates to the field of in-situ testing of plant airflow resistance characteristics, and provides a suitable in-situ testing method for plant airflow resistance characteristics. It employs a portable, quick-assembly in-situ DC wind tunnel in conjunction with a handheld anemometer and anemometer. The DC wind tunnel consists of a portable bed-type lifting frame and a wind tunnel device mounted on it, allowing for free adjustment of the test support platform's ground clearance, thus enabling flexible adjustment of the wind tunnel body, i.e., the height of the test port. Using this DC wind tunnel structure, the wind field at any wind speed can be reproduced by adjusting the variable frequency fan in the power section. Combined with the handheld anemometer and anemometer, the wind speed and pressure values ​​before and after the plant are measured. The average value of each measuring point before and after is taken as the final measured wind speed and pressure value. Based on the measured pressure drop and wind speed, the drag coefficient at different heights of the plant is calculated, thereby enabling in-situ testing of the plant's aerodynamic resistance characteristics at different heights and wind speeds.

The application discloses a correction method of dynamic particle drag coefficient considering the wall constraint of limited space, which comprises the following steps: firstly, a physical model of a solid-liquid two-phase flow calculation domain and two-phase coupling control equations are constructed to obtain basic parameters for numerical calculation; secondly, wall constraint characteristic parameters are calculated based on the spatial coordinates of particles and the model wall, and a wall constraint correction factor is constructed according to the wall constraint characteristic parameters; then, the correction factor and a particle concentration correction factor are determined in combination with working condition boundary conditions; subsequently, the above parameters and the correction factors are introduced into a drag coefficient calculation model to obtain a dynamic correction drag coefficient which takes into account the wall constraint effect and the particle concentration influence; the particle drag is calculated and coupled to the two-phase control equations as a momentum exchange source term; the flow and particle motion states are iteratively updated until convergence. The application is suitable for a cross-scale flow environment where the main flow and the gap flow channel coexist, can effectively improve the accuracy of real simulation, and can provide technical support for the analysis and optimization design of solid-liquid two-phase flow of fluid machinery and process equipment.

The invention belongs to the technical field of hypersonic aircraft design, and particularly relates to a method for determining the speed, range and height of an aircraft based on a constant flight path angle, and the method comprises the steps: 1, calculating the mass m1 of the aircraft at the end of boosting; step 2, calculating the speed V1 of the aircraft at the end of boosting, wherein V0 is the initial speed of the aircraft; c is the effective exhaust speed of the aircraft; m0 is the initial mass of the aircraft; cD is the resistance coefficient of the aircraft; cL is the lift coefficient of the aircraft; g is gravitational acceleration; gamma is a flight path angle; t1 is the boosting ending time of the aircraft; 3, the range x of the aircraft is calculated; 4, the height z of the aircraft is calculated according to the formula that z = x tan gamma.

This invention relates to the field of automotive aerodynamics and intelligent design technology, providing a method for automotive aerodynamic optimization based on vortex characteristics and ternary coupled AI. The method includes: dividing the wake into multiple rectangular wake zones based on vortex characteristics according to vehicle type; parametrically deforming the rear region of the vehicle; extracting the regional average value of vortex characteristic quantities within each wake zone through flow field numerical simulation; constructing a ternary coupled dataset of geometric features, wake zone features, and drag coefficients; constructing and training a ternary coupled AI model; using the trained ternary coupled AI model to predict the wake zone features and drag coefficients of new samples; combining contribution analysis and global optimization to obtain optimization priorities; and providing feedback on the features most deserving optimization. This invention achieves accurate prediction and targeted optimization of the aerodynamic characteristics of the vehicle rear, improving aerodynamic optimization efficiency.

The present application relates to the field of aerodynamics, and discloses a three-dimensional aircraft lift-drag force prediction method, system, device and storage medium, wherein the method comprises: constructing a three-dimensional aircraft digital model of multiple shape parameters, generating a first aerodynamic data set and a second aerodynamic data set in combination with different working condition parameters, and performing normalization and standardization processing on the aerodynamic data; the data precision of the first aerodynamic data set is lower than that of the second aerodynamic data set; an initial prediction model of the three-dimensional aircraft lift-drag force is constructed based on a variational autoencoder, a pre-training model is obtained by training the first aerodynamic data set, and a final prediction model is obtained by continuing to train the second aerodynamic data set; the point cloud data of the aircraft to be predicted after preprocessing and target working condition parameters are input into the final prediction model, and corresponding lift coefficients and drag coefficients are output. The present application can adapt to the input of different shape parameters and different working condition parameters, and can realize rapid prediction of the three-dimensional aircraft lift-drag force.

The invention discloses a commercial vehicle transmission system equivalent rotational inertia calibration and mass real-time estimation method, and relates to the technical field of vehicle dynamics control. Identifying the product of the equivalent merging coefficient K1 of the rolling resistance and the ramp resistance and the current mass mk and the air resistance coefficient K2 under the no-load state of the vehicle; and under the acceleration working condition, based on the obtained K1mk and K2 values, the equivalent transmission system rotational inertia Ii and the servicing no-load mass mk are identified. And in a quality real-time estimation stage after leaving a factory, updating the sum of products with the current mass mtotal in real time in a constant-speed driving segment. And in an acceleration working condition, Ii calibrated before leaving a factory is implanted into the kinetic model as a fixed parameter, and based on the updated mtotal sum value, the current total mass mtotal is directly solved through the relation between the driving force and the acceleration. According to the method, the strong coupling problem of the rotational inertia and the mass during estimation is thoroughly solved, and the real-time performance, precision and reliability of mass estimation in the vehicle running process are remarkably improved.

The invention discloses an AI-enhanced floating turbine six-degree-of-freedom motion actuation line calculation method, and belongs to the crossing field of computational fluid mechanics and ocean renewable energy technologies. Comprising the following steps: S1, constructing a basic actuating line model, taking a discrete blade as a blade element, and calculating an initial flow field and hydrodynamic parameters; s2, a three-level coordinate transformation system is established, and speed and attack angle correction of six-degree-of-freedom motion is completed; s3, predicting a dynamic lift-drag coefficient based on the time sequence features through a pre-trained deep learning agent model; s4, smoothly mapping the blade element hydrodynamic force into a flow field momentum source item, and solving a transient flow field in combination with CFD; and S5, constructing a'motion-flow field-hydrodynamic force 'iterative closed loop to realize dynamic coupling simulation. According to the method, the advantages of physical modeling and data driving are fused, the dynamic load prediction deviation is reduced, the calculation efficiency is improved compared with that of a full-geometric LES, and the method can be widely applied to optimization design and performance evaluation of the floating water turbine.

This invention discloses a high lift-to-drag ratio, long-endurance, low-speed airfoil, revealing its maximum relative camber, maximum relative thickness, and the curve equations satisfied by its upper and lower edges. The origin of the coordinate system containing the airfoil is defined as the leading edge of the chord. The X-axis coincides with the chord line, pointing from the leading edge to the trailing edge of the airfoil. The Y-axis is perpendicular to the X-axis, pointing in the direction of the airfoil's curvature. The chord length is defined as C; therefore, the maximum relative camber is 6%C, and the maximum relative thickness is 4.5%C. The airfoil of this invention exhibits a higher lift-to-drag ratio and a higher lift coefficient while maintaining a lower drag coefficient. It reduces the weight of the wing structure, and its thin, curved shape results in a smaller internal wing cavity, optimizing aircraft weight while concentrating stress on the structure.