This study evaluates the capability of the Simulating WAves Nearshore(SWAN)wave model(version 41.01)in predicting significant wave height and spectral peak energy content for swell waves in very shallow water of surf ...This study evaluates the capability of the Simulating WAves Nearshore(SWAN)wave model(version 41.01)in predicting significant wave height and spectral peak energy content for swell waves in very shallow water of surf zone during depth-induced wave breaking and dissipation.The model results were compared with field measurements at five nearshore stations.The results demonstrated that some breaker index formulations were successful for significant wave height prediction in surf zones.However,an incorrect shape of the energy spectrum and overestimated near spectral peak energy content at shallow water stations were obtained using all of the embedded depth-induced wave breaking formulations in SWAN.The dependent breaker index on relative depth(Kpd)formulation,which was successful in predicting near spectral peak energy content,resulted in an average error of 30%.Finally,this formulation was modified to enhance the model performance in reproducing the spectral peak energy content.展开更多
This study focuses on the development of a farm of tidal turbines in the Khuran Channel.The important factors include the location of turbines and their hydrodynamic effects on the environment.A three-dimensional circ...This study focuses on the development of a farm of tidal turbines in the Khuran Channel.The important factors include the location of turbines and their hydrodynamic effects on the environment.A three-dimensional circulation model for the Persian Gulf is employed for the comprehensive evaluation of the tidal energy potential throughout the study area.The model is validated by using in situ observations of water level and current data.The appropriate potential points for extracting the tidal energy were identified in the Persian Gulf using the model results.The Khuran Channel,located in the north of Qeshm Island,was found to be the best place to extract tidal energy inside the Persian Gulf.By adding the term of momentum losses to the governing equations,the feedback of extracting energy on the hydrodynamic around Qeshm Island was studied.The simulation results show that the average daily power production of a tidal farm with 99 turbines for one month is approximately 1.3 MW.This tidal farm also has a significant impact on the water level inside the Khuran Channel,especially near the tidal farm where these fluctuations exceed 4 cm.The change in the current speed caused by wake reaches 0.4 m/s.Wake effects were active up to 7 km downstream of the turbines.The current velocity was also estimated to be 1.6 m/s and 2.1 m/s during the spring and ebb tides within the channel,respectively.展开更多
Soil erosion is a serious threat to soil and water resources in semi-arid regions.Modified Pacific Southwest Inter Agency Committee(MPSIAC)and Erosion Potential Method(EPM),as two well-known models,have shown their pe...Soil erosion is a serious threat to soil and water resources in semi-arid regions.Modified Pacific Southwest Inter Agency Committee(MPSIAC)and Erosion Potential Method(EPM),as two well-known models,have shown their performance in many case studies.The goal of present study is to assess the efficiency of these methods for estimating the sediments yield and erosion intensity within short-term and longterm timeframes over two sub-basins of Dez watershed,west of Iran.The results showed that the study area can be categorized into slight,moderate,high and very high erosion zones.Almost half of the study area is highly susceptible to erosion due to the geological formations and land cover.Moreover,the longterm(i.e.30 years)sediment yield of 387 and 615(kton)y^(-1) estimated by MPSIAC and EPM models demonstrated the superiority of EPM.Compared to the measured value of 612(kton)y^(-1),the performance of EPM was astonishing.By splitting the dataset into six periods of five years,the sediment yield was predicted in short-term periods by both aforementioned methods.Such segmentation provides the opportunity to evaluate the impact of extreme flooding events on the models performances.The results showed that both models failed in estimation of sediment load during flood conditions.Nevertheless,the correlation coefficients for estimating the sediment yield were found to be R=0.93 and R=0.85 for EPM and MPSIAC models respectively,for short-term simulations.展开更多
基金supported by Iranian National Institute for Oceanography and Atmospheric Science
文摘This study evaluates the capability of the Simulating WAves Nearshore(SWAN)wave model(version 41.01)in predicting significant wave height and spectral peak energy content for swell waves in very shallow water of surf zone during depth-induced wave breaking and dissipation.The model results were compared with field measurements at five nearshore stations.The results demonstrated that some breaker index formulations were successful for significant wave height prediction in surf zones.However,an incorrect shape of the energy spectrum and overestimated near spectral peak energy content at shallow water stations were obtained using all of the embedded depth-induced wave breaking formulations in SWAN.The dependent breaker index on relative depth(Kpd)formulation,which was successful in predicting near spectral peak energy content,resulted in an average error of 30%.Finally,this formulation was modified to enhance the model performance in reproducing the spectral peak energy content.
文摘This study focuses on the development of a farm of tidal turbines in the Khuran Channel.The important factors include the location of turbines and their hydrodynamic effects on the environment.A three-dimensional circulation model for the Persian Gulf is employed for the comprehensive evaluation of the tidal energy potential throughout the study area.The model is validated by using in situ observations of water level and current data.The appropriate potential points for extracting the tidal energy were identified in the Persian Gulf using the model results.The Khuran Channel,located in the north of Qeshm Island,was found to be the best place to extract tidal energy inside the Persian Gulf.By adding the term of momentum losses to the governing equations,the feedback of extracting energy on the hydrodynamic around Qeshm Island was studied.The simulation results show that the average daily power production of a tidal farm with 99 turbines for one month is approximately 1.3 MW.This tidal farm also has a significant impact on the water level inside the Khuran Channel,especially near the tidal farm where these fluctuations exceed 4 cm.The change in the current speed caused by wake reaches 0.4 m/s.Wake effects were active up to 7 km downstream of the turbines.The current velocity was also estimated to be 1.6 m/s and 2.1 m/s during the spring and ebb tides within the channel,respectively.
基金The authors wish to thank the Khuzestan Water and Power Authority for data sharing.The Arca Company is also acknowledged for their GIS support.The authors also thank valuable comments made on an earlier draft from M.N.Allahdadi,Louisiana State University。
文摘Soil erosion is a serious threat to soil and water resources in semi-arid regions.Modified Pacific Southwest Inter Agency Committee(MPSIAC)and Erosion Potential Method(EPM),as two well-known models,have shown their performance in many case studies.The goal of present study is to assess the efficiency of these methods for estimating the sediments yield and erosion intensity within short-term and longterm timeframes over two sub-basins of Dez watershed,west of Iran.The results showed that the study area can be categorized into slight,moderate,high and very high erosion zones.Almost half of the study area is highly susceptible to erosion due to the geological formations and land cover.Moreover,the longterm(i.e.30 years)sediment yield of 387 and 615(kton)y^(-1) estimated by MPSIAC and EPM models demonstrated the superiority of EPM.Compared to the measured value of 612(kton)y^(-1),the performance of EPM was astonishing.By splitting the dataset into six periods of five years,the sediment yield was predicted in short-term periods by both aforementioned methods.Such segmentation provides the opportunity to evaluate the impact of extreme flooding events on the models performances.The results showed that both models failed in estimation of sediment load during flood conditions.Nevertheless,the correlation coefficients for estimating the sediment yield were found to be R=0.93 and R=0.85 for EPM and MPSIAC models respectively,for short-term simulations.
