To explore the treatment capacity of an integrated wastewater treatment system for freshwater pond aquaculture wastewater,this study selected an aquaculture base in Chongqing with an integrated wastewater treatment system.According to the water quality evaluation indexes in"Requirement for Water Discharge from Freshwater Pond Aquaculture"(SC/T 9101-2007),the water quality of aquaculture wastewater and effluent from various treatment units was measured and analyzed.The results showed that the annual average suspended matter content(TSS),5-day biochemical oxygen demand(BOD5),permanganate index(CODMn),total nitrogen(TN),and total phosphorus(TP)removal efficiencies were 67.30%,77.13%,39.31%,48.39%and 52.62%in the comprehensive wastewater treatment system,and the removal effect was obvious.After the wastewater treatment system is used to treat the aquaculture wastewater,the treated aquaculture wastewater is all lower than the level 1 standard of"Requirement for Water Discharge from Freshwater Pond Aquaculture",and the wastewater can be directly discharged or recycled.The research shows that the integrated wastewater treatment system has an obvious effect on aquaculture wastewater treatment and can effectively control the pollution index of aquaculture wastewater,which has a positive significance for improving the aquaculture environment and reducing aquaculture pollution.
This study proposes a lightweight underwater image restoration method to obtain high-quality biological images and address issues such as color cast and low contrast.The process compensates for color distortion in underwater images through global averaging and max pooling,reducing the influence of irrelevant features in the input images and enhancing the model′s focus on key features.It introduces ghost convolution to reduce redundancy in feature maps and model parameters.Additionally,dynamic convolution is used to adjust the brightness and contrast of images in three color spaces adaptively.The results show that the proposed model outperforms contrast methods based on non-physical and physical models in terms of peak signal-to-noise ratio(PSNR)and structural similarity index(SSIM),with values of 24.298 and 0.891,respectively,on the Enhanced Underwater Vision Perception(EUVP)underwater scene dataset.Compared to the deep learning models Shallow-Uwnet and Water-Net on the EUVP underwater biological image dataset,the proposed model achieves computational efficiency of only 0.27%and 0.04%,respectively.The improved images show an SSIM improvement of 3.77%and 6.72%,compared to the two aforementioned models.By directly adjusting pixel values to restore underwater image colors,this model occupies only 41 KB of storage space,making it suitable for deployment on underwater robots.This study demonstrates that the proposed model effectively enhances underwater biological images,and due to its low computational load and storage requirements,it contributes to the accurate support of ocean data and promotes the development of marine resources.
To study the hot air drying characteristics of Antarctic krill and establish a drying model.Methods:Using frozen Krill as raw material,the effects of different temperature and drying quantities on the drying time and drying rate of krill were studied,and the effective diffusion coefficient and drying activation energy of krill were analyzed under different drying conditions.Five drying models,Lewis,Henderson and Pabis,Page,Modified Page,Wang and Singh,were used to fit the test data.The optimal drying model was determined and validated with the determination coefficient R2,Chi-square test value X2,root mean square error M and error fair sum S as the model fitting effect evaluation indexes.Results:The drying time was shortened and the drying rate increased with the increase in temperature or decreased drying quantities.The influence of drying amount on drying time and drying rate was less than that of temperature.When the temperature was 50-100℃,the effective diffusion coefficient of water was 1.459×10-8-6.310×10-8,and the dry activation energy was 29.599 kJ/mol.When the drying amount was 0.5-3.0 kg,the effective diffusion coefficient of water was 4.630×10-9-3.533×10-8.By comparing the fitting effect evaluation indexes of the five models,it was found that the Page model had a high R2 value and a low X2,M and S value,which could better fit the test data of Antarctic krill.The model's predicted value had a high degree of coincidence with the test value,and it could accurately predict the change law of water ratio in the hot-air drying process of Antarctic krill.Conclusion:Increasing the temperature or decreasing the drying amount can shorten the drying time and increase the drying rate.Page model can accurately describe the hot-air drying process of Antarctic krill,and provide a theoretical basis for predicting and controlling the hot-air drying process of Antarctic krill.
To investigate the effect of different C/N on the accumulation of off flavor in biofloc reactor,different initial DOC/DIN(Dissolved organic carbon,DOC:Dissolved inorganic nitrogen,DIN)gradients were set up for group A(no glucose added,C/N of 6),group B(C/N of 10)and group C(C/N of 20)by adding glucose to the bioflocs released from shrimp farming and a 7-day experiment was conducted.Water quality monitoring was carried out everyday.The concentrations of Geosmin(GSM)and 2-Methylisoborneol(2-MIB)in the BFT water were detected at the beginning and end of the experiment and the flocs were taken for nutrient index detection.The results showed that the accumulation of Geosmin(GSM)and 2-Methylisoborneol(2-MIB)was 22.41 ng/L and-0.19 ng/L at C/N of 10,which were significantly lower than those in the C/N of 6 group(76.4 ng/L and 4.43 ng/L)and C/N of 20 group(50.98 ng/L and 3.52 ng/L),respectively;the total ammonia nitrogen and nitrite nitrogen concentrations were lower than 0.10 mg/L and 0.15 mg/L,respectively,in all groups during the experiment;the crude protein content of bioflocs was highest at 31.64%±0.22%at C/N of 10.It was shown that the addition of glucose can effectively reduce the accumulation of GSM and 2-MIB production,and the most effective of reducing the accumulation of GSM and 2-MIB production was achieved when the C/N in the biofloc reactor was 10,as well as having water quality improvement effect.
To solve the industrial bottlenecks of the traditional pond aquaculture of the Scylla paramamosain,such as mutual killing,severe losses caused by natural disasters,and the cumbersome operation of the existing factory circulating aquaculture system of"Crab Apartment",the Scylla paramamosain was cultured in the"Dragon Boat"type factory circulating aquaculture system and the factory circulating aquaculture system of"Crab Apartment"designed in this experiment.The breeding cycle was 30 d.The study aimed compare the survival rate,aquaculture water environment,growth performance and nutritional quality.The results showed as follows:The survival rate of the Scylla paramamosain in the dragon-boat type factory circulating aquaculture system was(98.66±0.58)%,which was significantly higher than that in the crab apartment factory circulating aquaculture system(P<0.05).In the"Dragon Boat"type industrial recirculating aquaculture system,the ammonia nitrogen content was 0.062 5-0.067 1 mg/L,the nitrite nitrogen content was 0.021 3-0.025 3 mg/L,and the active phosphate content was 0.031 5-0.034 6 mg/L,all of which were lower than that in the"Crab Apartment"industrial recirculating aquaculture system.The body weight specific growth rate of the"Dragon Boat"type factory recirculating aquaculture system was(3.43±0.50)%/d,the molting interval time was(20.4±0.25)d,and the growth performance was significantly higher than that of the"crab flat"factory recirculating aquaculture system(P<0.05).The essential amino acid index(E)in muscle of the Scylla paramamosain cultured in the"Dragon Boat"type industrial recirculating aquaculture system was 67.35,which was higher than that in the"Crab House"industrial recirculating aquaculture system;The fatty acid composition and quality safety of muscle were better than that of"Crab Apartment"industrial circulating aquaculture system.The results showed that the adoption of the"Dragon Boat"type industrial recycle aquaculture system could reduce water pollution,improve the survival rate and growth rate of the crab,improve muscle nutrition and reduce the content of heavy metals in the muscle,which could be used as a new model for the industrial culture of the crab.
In the realm of intensive aquaculture,real-time monitoring of fish feeding status is one of the important bases for developing scientific feeding strategies.To achieve temporal detection of fish feeding states,and to solve the problem of high error in detecting feeding state switching by existing methods,this paper proposes a fish state detection network BMN-Fish based on an improved BMN(Boundary Matching Network),which introduces an efficient depth module and consists of an Efficient Channel Attention Module Net(ECANet)and a Base Residual Module(BRM).Among them,the Efficient Channel Attention Module can expand the perceptual field of the temporal dimensional features,to improve the ability of the model to extract local information;the Base Residual Module enables the algorithm to focus on the regions of interest in the feature map,which can strengthen the global perception ability of the algorithm.The experimental results showed that the AUC and AR@100 of BMN-Fish were 93.32%and 95.28%,which were 2.17%and 1.95%higher than BMN,respectively.BMN-Fish could effectively detect the sequential feeding movements of fish,and provide important information for formulating intelligent feeding strategies for intensive aquaculture.
Pelagic fishery is still faced with the problems of low automation and intelligence levels.As the traditional method of catch statistics is counting by people,which wastes time and energy,automatic catch statistics has become one of the hot spots in the study of pelagic fisheries.To solve this problem in the pelagic tuna fishery,this paper presents an automatic counting method based on the DP-YOLO(DCNv2-PConv-YOLO)model combined with a dynamic detection gate algorithm.Due to the lightweight nature of YOLOv7-tiny,it is treated as a baseline model.Using deformable convolution,DCNv2 can obtain more shape features.To alleviate the speed decrease caused by adopting DCNv2 and ensure that it can work on edge devices,partial convolution PConv replace replace regular convolution to improve detection speed,and reduce the hardware·s model computation and performance demands.The dynamic detection gate algorithm is designed to avoid repeated counting.Meanwhile,a new miscounting error index called ECE(Error Counting Error)is proposed to evaluate the counting method.To verify the influence of the module on YOLOv7-tiny,ablation test results show that DP-YOLO not only reduces 3.3%of parameters,23.7%of calculation time and 2.1%of calculation time,but also increases the average accuracy by 5.3%.The test results of automatic catch statistics show that the identification accuracy of this method is 95.8%,the counting accuracy achieves 97.9%,and ECE is only 2.1%,which is respectively 45.8%and 25%higher than the existing counting algorithms of YOLOv5s+ Deepsort and YOLOv7-tiny+Deepsort.This algorithm provides a novel method of automatic counting catch for pelagic fishery.Therefore,the study can meet the catch statistics requirements of tuna longline fishing.
Aiming at the problem that the inclination angle is too large and easy to roll over when the sinking and floating aquaculture cages are sinking and floating.In this study,an automatic control and management system for sinking and floating aquaculture cages has been developed.The automatic control system of sinking and floating aquaculture cages is mainly based on PID control technology.To realize automatic control of the inclination angle of cages,the appropriate parameters of the PID control system which uses the inclination angle signal and control algorithm to adjust the actuator,are explored.The corresponding management system for automatic control of sinking and floating aquaculture cages has been developed.The main functions include:floating and sinking control,cage cleaning,GPS positioning,and camera cleaning,as well as underwater camera monitoring,water quality,flow rate,liquid level and pressure data monitoring,etc.After a series of experiments such as the buoyancy-gravity ratio of the cage,the water inlet diameter and diameter ratio of the adjusting buoy,the PID control,the suitable value of the buoyancy-gravity ratio of the cage is 1.2,the water inlet diameter and diameter ratio of the adjusting buoy is 0.03.The PID parameters are P:100,I:1 000,and D:0.In this study,the control and information of each module of the sinking and floating aquaculture cages were integrated into a set of system,which improved the performance of the automatic control system of the deep-sea aquaculture cages.The system can control the output in a timely and stable manner and achieve the stable sinking and floating of the aquaculture cages.The results of the research have certain theoretical and practical meaning.The automatic control system of deep-sea sinking and floating aquaculture cages is one of the important technical means to achieve the industrialization development of deep-sea aquaculture.The research methods and experimental results proposed in this paper provide important data reference and theoretical basis for the research and application of deep-sea sinking and floating aquaculture cages.
In order to understand the effect of low-frequency vibration stimulation on the behavior and physiology of Larimichthys crocea,this study simulated the vibration of breeding cabin by self-made steel sink and actuator,and used the main frequency of underwater noise of traditional knocking operation to catch large yellow croaker.The frequency of 125 Hz(150 dB)and 200 Hz(150 dB)were used to conduct vibration stimulation experiments on 250 g and 500 g groups of large yellow croaker to determine the behavioral response and physiological and biochemical changes of large yellow croaker(cortisol,epinephrine,thyroxine).The results showed that:(1)In the early stage of acoustic stimulation,the behavioral responses of the two groups of test fish were characterized by random movement,cruising away after slow approach,free or around cruising.After adaptation,the test fish were basically in a regular or free cruising around the wall,cruising away after slow approach,or stagnant,and there was no obvious disturbance response.(2)In 250 g test group,the change of adrenaline at 125 Hz frequency(about 40.93%increase)was the most significant(P<0.05).Under the condition of 200 Hz frequency,the change of thyroxine(increased by about 41.08%)was the most significant(P<0.05).Except for increase of other blood indexes except epinephrine was higher than that of 125 Hz frequency group.Therefore,250 g large yellow croaker was more sensitive to 200 Hz.In the 500 g test group,the change of thyroxine(increased by about 28.68%)at 125 Hz frequency was the most significant(P<0.05),and other blood indexes decreased.Under the condition of 200 Hz frequency,the change of thyroxine(increased by about 41.79%)was the most significant(P<0.05)and higher than that of 125 Hz frequency group,while other blood indexes increased in different degrees in 200 Hz frequency group.Therefore,the 250 g and 500 g groups were more sensitive to 200 Hz vibration stimulation.In this study,the effects of low-frequency vibration stimulation on the behavioral response and physiological and biochemical indexes of large yellow croaker were analyzed.The aim was to improve the growth rate,survival rate and quality of large yellow croaker during the breeding process of large yellow croaker,and to provide data support and reference.
To clarify the selectivity of beam shrimp trawl for Parapenaeopsis hardwickii and Solenocera melantho,authors conducted the selectivity tests of different mesh sizes in December 2018 and March to April 2019,respectively.The results showed that:In December,the experiment mainly focused on catching Parapenaeopsis hardwickii,whose body length ranged from 35 to 100 mm,with an average body length of 66 mm;in the investigation from March to April,the main fishing was Solenocera melantho,whose body length ranged from 30 to 140 mm,with an average body length of 60 mm.With the increase in mesh size,the average body length of Parapenaeopsis hardwickii increased from 71 to 74 mm,and the average body length of Solenocera melantho increased from 64 to 74 mm.The mesh size significantly affected the body length of the two types of shrimp.When the mesh size for Parapenaeopsis hardwickii was 25 mm,28 mm and 38 mm,its L50 was 55.334 mm,57.396 mm and 68.319 mm;when the mesh size for Solenocera melantho was 22 mm,25 mm,28 mm and 38 mm,its L50 was 54.919 mm,62.734 mm,72.807 mm and 74.819 mm.The equations for the relationships between the mesh size of the codends and L50 for Parapenaeopsis hardwickii and Solenocera melantho,respectively,are as follows:L50=1.023 m+29.331(R2 = 0.995),L50 = 1.134 m+34.280(R2= 0.724).As the mesh size of codends increased(25-38 mm,22-38 mm),the selectivity curves of both Parapenaeopsis hardwickii and Solenocera melantho shifted sequentially to the right,and the selectivity curves both showed crossover phenomena,which were inseparable from the body shape characteristics of the shrimp.To release shrimps with body length less than 70 mm,it is recommended that the mesh size of codend should not be less than 39.75 mm during the main catch of Parapenaeopsis hardwickii;The mesh size of codend should not be less than 31.50 mm during the main catch of Solenocera melantho.The results of this study can provide a reference for the management of beam shrimp trawl and the protection of two kinds of shrimp resources in the East China Sea.
Biofloc technology(BFT)has been proven to perform closed,high-density aquaculture at a lower cost and has received much attention from aquaculturists in recent years.The two critical services of bioflocs in BFT aquaculture systems include removing ammonia nitrogen from feeding and providing nutrients for some cultured animals.The current experiment investigated the ammonia nitrogen removal efficiency and nutrient composition of bioflocs under the condition of two bioflocs concentrations(300 mg/L and 600 mg/L)and three Bacillus subtilis additions(104 CFU/mL,105 CFU/mL and 106 CFU/mL)in the suspended growth reactors.The results showed that the bioflocs concentration had a significant effect(P<0.05)on the removal rate of ammonia nitrogen.The highest ammonia nitrogen removal rate was(3.85±0.27)mg N/h observed in the group with 600 mg/L bioflocs and 106 CFU/mL Bacillus subtilis,which was significantly higher than that in the 300 mg/L bioflocs groups.The bioflocs concentrations significantly affected the significant nutrients(crude protein,crude ash,crude fat)and some amino acids in the bioflocs.Biofloc concentrations had no significant effect on the content of major nutrient(crude protein,crude ash,crude fat)and some amino acids in the biofloc(P>0.05).The crude protein content of the bioflocs was(27.22±0.47)%and(27.43±1.07)%for the 300 mg/L and 600 mg/L bioflocs groups with the Bacillus subtilis addition level of 106 CFU/mL,which was significantly higher than the other two bacteria addition levels.The copy numbers of four nitrification genes(ureC,amoA,nxrA,Hao)were higher in the groups at a concentration of 600 mg/L than in the 300 mg/L groups.The copy numbers of amoA,ureC and Hao genes in bioflocs increased with the addition of Bacillus subtilis.The results of the current study proved that the 600 mg/L bioflocs and 106 CFU/mL Bacillus subtilis were beneficial in improving the ammonia nitrogen removal rate and nutritional content of the bioflocs.
In order to realize the high-value utilization of low-value fish products,this study prepared the silver carp hydrolysate by enzymatic hydrolysis,and constructed the Maillard reaction(MR)system with xylose to study the effect of ultrasound-assisted MR on the flavor characteristics of the hydrolysate,and compared with the traditional wet MR and enzymatic hydrolysis.The results showed that the ultrasonic pretreatment could promote the generation of intermediates and the degree of browning and improve the rate of the MR;the fluorescence intensity of the hydrolysate decreased after the MR,indicating the introduction of hydroxyl groups.Compared with the hydrolysate,the bitter amino acids of the ultrasound-assisted Maillard reaction products(MRPs)were reduced by 18%,which was better than the un-sonicated group.The results of MMSE-GC-MS and electron tongue showed that the volatile compounds(benzaldehyde,furfural and 2-ethylfuran,etc.)of the ultrasound-assisted MRPs contributed to the aroma enhancement were higher in the products,and the bitterness and astringency were lower than those of the hydrolysate and the MRPs.The above results indicate that the ultrasonic treatment can effectively improve the flavor characteristics of the hydrolysate and provide a reference for the development of freshwater fish products.
为探究背角无齿蚌(Anodonta woodiana)对养殖水体亚硝酸盐氮(NO-2-N)的净化效果,分析了亚硝酸盐氮(1.0 mg/L)暴露组背角无齿蚌相较于亚硝酸盐氮空白组(0 mg/L)的滤水率的影响,进而通过构建受亚硝酸盐氮(1.0 mg/L)污染的微型生态系统,比较了对照组(0 只/m3)、低(10 只/m3)、中(20 只/m3)和高(30 只/m3)养殖密度背角无齿蚌及其不同处理时间(24、48、72 和 96 h)交互作用下亚硝酸盐氮的含量、去除率与净化效率变化.结果显示:空白组和亚硝酸盐氮暴露组背角无齿蚌的滤水率分别为 232.1±122.3 L/(h·kg)和 69.0±17.7 L/(h·kg),两者之间差异不显著(P>0.05);低养殖密度背角无齿蚌处理96 h后的养殖水体亚硝酸盐氮含量最低,为 0.20±0.06 mg/L,相应的去除率和净化效率分别可达到(64.99±10.32)%和 90.16±13.54 mg/(h·kg);背角无齿蚌对亚硝酸盐氮含量及去除率的影响与养殖密度和处理时间显著相关(P<0.05),与两者的交互作用关系不显著(P>0.05),而对亚硝酸盐氮的净化效率仅与养殖密度显著相关(P<0.05).研究表明,背角无齿蚌能够有效净化养殖水体中较高含量的亚硝酸盐氮,养殖密度设定为 10 只/m3 的净化效果最佳.
拖网网板的水动力模型试验结果经常会因雷诺数、模型尺度等各种试验因素出现不同程度的结果偏差.为研究模型参数对拖网网板水动力试验的影响机理,选取立式V型曲面网板为研究对象,基于水槽模型试验结合计算流体力学数值模拟方法,对比分析其水动力性能及流场分布,探究模型尺度比、板面厚度及模型材料等参数对其水动力试验结果的影响.结果显示:模型尺度比变化对网板升/阻力系数曲线形状无显著影响,但模型尺度缩小过多(20∶1)将导致升力系数在小冲角(α<30°)时偏差明显;模型板面厚度增加会导致升力系数在大冲角(α>30°)下的显著降低,而对阻力系数的影响则主要反映在小冲角(α<30°)时;非金属材料模型由于刚性不足,在水槽模型试验过程中容易因受力后产生一定位移与变形而引起试验结果的偏差.基于上述结果,设计网板水动力模型试验时,应使得模型尺度尽可能大,减小模型尺度对试验结果精度的影响;可适当增加板面厚度以提高模型结构稳定性,增厚范围不宜超过 2 倍.
桁架式等深远海养殖网箱的养殖网由网纲和网衣组成,在无遮蔽海域将遭受更为严峻的海洋环境条件.为衡量承力网纲的最大张力与面法向偏移,采取一种耦合Morison模型和Screen模型计算网纲和网衣水动力载荷的有限元方法.以不同水深位置、上下相互独立的两片养殖网A和B为研究对象,开展网箱坐底时承力网纲在纯流、波流联合作用下的张力响应研究.对数值计算结果进行统计性分析发现,纯流条件下的网纲平均最大张力和面法向平均最大偏移随流速增加而增加;波流联合作用下养殖网A的网纲平均最大张力和面法向平均最大偏移随设计波周期的增加而减小,养殖网B则逐渐增加,总体上A的结果显著大于B.本研究成果对网纲和网衣耦合的有关研究具有参考作用.
为了实现鱼片的自动化、节能化切段操作,设计了一种基于深度学习的识别鱼片轮廓并规划切割路径的控制系统.使用深度学习模型对采集到的鱼片图像进行实例分割,根据识别结果规划切割路径,并由固定有高压水喷嘴的切割执行机构完成鱼片切段作业.目标检测试验中,在Mask R-CNN的基础上改进算法,加入Mosaic数据增强方法,主干网络使用ResNetXt50 并加入注意力机制SKNet.改进后的模型检测精度达到98%,平均检测时间为 0.058 s,相对于以ResNet50 为主干网络的原模型,在检测时间仅增加 0.001 s的基础上将检测精度提高了 9.9%.鱼片切段试验中,平均切割合格率达到 90%.研究表明,该系统可准确快速识别鱼片轮廓,高效完成鱼片切割作业,为未来向着智能化方向发展的水产品加工行业提供了新思路.
针对目前水产养殖过程中水质监测方式存在效率低、实时性差、工作区域受限制等缺点,设计了一种基于STM32 与树莓派的水质监测无人艇系统.系统采用STM32 单片机和树莓派 4B作为控制器,结合GPS模块和电子罗盘实现无人艇的航行控制;利用摄像头、pH、浊度、温度传感器实时采集水体环境和水面图像数据;通过 4G通信模块实现数据传输.在阿里云服务器上部署基于.NET Framework框架开发的上位机软件,实现对无人艇的指令下发以及可视化显示采集到的数据等功能.结果显示:养殖水质监测无人艇到达的实际测量区域与预设区域位置误差最大为 4.3 m,最小为 3.4 m,精度范围满足实际需求;水质测量平均用时在7 min 28 s左右,相比传统人工检测方式,作业效率显著提升.研究表明:本系统运行稳定,操作方便,能够及时有效地获取养殖水域水体数据,提高了养殖人员的工作效率,降低了养殖成本,具有一定的应用前景.
臭氧作为一种强氧化剂,常用作移动床生物膜反应器(Moving Bed Biofilm Reactor,MBBR)系统的杀菌消毒剂.为了得到臭氧对MBBR处理水质的影响与对副溶血弧菌的杀菌效果,用 10 L反应器,在 60%填充率下,研究不同质量浓度臭氧(0、1、2、4、6 mg/L)对系统硝化能力与对副溶血弧菌(Vibrio parahaemolyticus)的杀灭效果.结果显示:与对照组相比,2 mg/L臭氧对滤料细胞死亡率影响不显著(P=0.49);总氨氮(TAN)去除率分别为 55.11%±5.32%、57.89%±9.01%、49.2%±5.99%、33.07%±2.68%、34.22%±8.89%;当臭氧通入量在 4 mg/L及以上时,TAN去除率显著低于其余组(P<0.05);臭氧剂量 2 mg/L及以上时,TCBS平板上未检测到副溶血弧菌(从 108 CFU/mL降低到不能被检测出的水平).综合考虑臭氧对滤料细胞死亡率、氨氮处理效率以及副溶血弧菌的杀菌率,MBBR池臭氧推荐使用质量浓度为 2 mg/L.
多波束渔用声呐是海洋渔业中不可或缺的设备,在探测鱼群方面发挥着重要作用.然而此类声呐的指向性容易受到风浪和船舶姿态的影响.为了解决这个问题,本研究建立了简化的姿态变化模型,指出了影响波束稳定误差的因素,并提出了一种基于卡尔曼滤波和数字波束形成技术的波束稳定算法:先对姿态值做滤波及插值处理,获得更平滑、采样率更高的姿态数据;再使用坐标旋转的方式对波束的目标指向进行补偿,从而实现声呐波束的稳定而精确的指向.本研究基于FPGA(现场可编程门阵列)实现了波束稳定模块.摆台模拟试验结果表明,在四级海况下,应用本模块可保证各波束指向角度最大偏差不超过±1.8°,与仿真结果基本一致.本研究已应用在多波束渔用声呐中,大大提高了渔船捕捞效率.
为探索海洋养殖与海上风电融合发展的可行性,以浮式网箱与垂直轴风机综合平台为研究对象,通过物理模型试验的方法研究该综合平台在规则波作用下的水动力响应;采用 1∶100 的比尺制作模型,通过CCD(电荷耦合)高速相机及自主开发程序分析运动幅值,并采用拉力传感器采集系泊拉力时域值.结果显示:浮式网箱与垂直轴风机综合平台在波高为 9 m的极限工况下,纵荡最大值为 4.75 m、垂荡最大值为 4.21 m、纵摇最大值为 8.35°,稳定性基本满足规范要求;在波浪作用下,浮式网箱与垂直轴风机综合平台的运动响应与系泊力均与波高呈正相关,纵荡和垂荡与波浪周期呈正相关,而纵摇和系泊力与周期呈负相关;同一工况下迎浪侧系泊力明显大于背浪侧系泊力,两者之间最大差值可达 75%.研究结果可为风渔融合结构的研发设计提供参考.
