The lattice Boltzmann (LB) method has progressively emerged as a viable numerical tool for studying the dynamics of fluid flows, gaining tremendous popularity given its simplicity, adaptability, and low computational costs associated with solving the Navier-Stokes (NS) equation and beyond. The recent integration of high-order LB models, containing larger quantities of discrete velocity terms have been found to provide enhanced numerical accuracy and stability. Fundamental opportunities for further developments in assessing the performance of these lattices is imperative for future progression and applications involving complex flows, such as turbulence modelling and multiphase mixtures. However, there is still little known when comparing the performance of different high-order models. To this aim, this work presents a numerical investigation into the accuracy and stability of different high-order lattice structures, using the double-shear layer (DSL) benchmark test. The results show that lattice structures with a larger quantity of discrete velocity terms are able to produce more stable and accurate results despite possessing the same order of equilibrium terms and isotropy gradients. Further highlighted is the stability dependence of certain lattice structures on their respective reference temperature. These findings serve to provide a preliminary understanding of when to apply certain lattice structures for specific applications.
{"title":"An Investigation into the Numerical Robustness of High-order Lattice Boltzmann Models","authors":"V. Dzanic, C. From, E. Sauret","doi":"10.14264/06b6d9b","DOIUrl":"https://doi.org/10.14264/06b6d9b","url":null,"abstract":"The lattice Boltzmann (LB) method has progressively emerged as a viable numerical tool for studying the dynamics of fluid flows, gaining tremendous popularity given its simplicity, adaptability, and low computational costs associated with solving the Navier-Stokes (NS) equation and beyond. The recent integration of high-order LB models, containing larger quantities of discrete velocity terms have been found to provide enhanced numerical accuracy and stability. Fundamental opportunities for further developments in assessing the performance of these lattices is imperative for future progression and applications involving complex flows, such as turbulence modelling and multiphase mixtures. However, there is still little known when comparing the performance of different high-order models. To this aim, this work presents a numerical investigation into the accuracy and stability of different high-order lattice structures, using the double-shear layer (DSL) benchmark test. The results show that lattice structures with a larger quantity of discrete velocity terms are able to produce more stable and accurate results despite possessing the same order of equilibrium terms and isotropy gradients. Further highlighted is the stability dependence of certain lattice structures on their respective reference temperature. These findings serve to provide a preliminary understanding of when to apply certain lattice structures for specific applications.","PeriodicalId":369158,"journal":{"name":"Proceedings of the 22nd Australasian Fluid Mechanics Conference AFMC2020","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130863690","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We consider the capillary trapping of carbon dioxide in a horizontal aquifer. Motivated by the heterogeneous nature of reservoir rocks, we allow the permeability to vary vertically across the aquifer. The CO 2 spreads under buoyancy following the end of the injection period. We derive a parabolic governing equation for the motion, which accounts for the trapping of CO 2 at the trailing edge. The flow behaves in a self-similar fashion at early times when it is confined and at late times when it is effectively unconfined. We determine how these similarity solutions are influenced by vertical heterogeneity. We quantify the late-time position of the leading edge of the CO 2 and show that it is highly sensitive to the permeability at the top of the aquifer but rather insensitive to the permeability structure elsewhere. Our results have important implications for the volume of CO 2 that may be stored at a particular geological site.
{"title":"Capillary trapping of CO2 in a heterogeneous horizontal aquifer","authors":"E. Hinton, A. Woods","doi":"10.14264/F23EDFC","DOIUrl":"https://doi.org/10.14264/F23EDFC","url":null,"abstract":"We consider the capillary trapping of carbon dioxide in a horizontal aquifer. Motivated by the heterogeneous nature of reservoir rocks, we allow the permeability to vary vertically across the aquifer. The CO 2 spreads under buoyancy following the end of the injection period. We derive a parabolic governing equation for the motion, which accounts for the trapping of CO 2 at the trailing edge. The flow behaves in a self-similar fashion at early times when it is confined and at late times when it is effectively unconfined. We determine how these similarity solutions are influenced by vertical heterogeneity. We quantify the late-time position of the leading edge of the CO 2 and show that it is highly sensitive to the permeability at the top of the aquifer but rather insensitive to the permeability structure elsewhere. Our results have important implications for the volume of CO 2 that may be stored at a particular geological site.","PeriodicalId":369158,"journal":{"name":"Proceedings of the 22nd Australasian Fluid Mechanics Conference AFMC2020","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117138239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The flow of viscous fluid from a line source on an inclined plane containing a topographic depression is studied using a lubrication model. The steady flow is perturbed by the depression. We focus on the regime in which the flow thickness is small relative to the lengthscale of the depression. For shallow depressions, the flow is only slightly perturbed. However, for deeper depressions a large pond of fluid with a horizontal free-surface is observed. This ponding of fluid is associated with the topography having uphill regions, which in the absence of inertia can only be surmounted by developing a deep fluid layer. The accumulation of fluid in the depression leads to a focusing of the flow, which is observed even far downstream of the depression.
{"title":"Free-surface viscous flow over a depression","authors":"E. Hinton, A. Hogg, H. Huppert","doi":"10.14264/DEAEB9F","DOIUrl":"https://doi.org/10.14264/DEAEB9F","url":null,"abstract":"The flow of viscous fluid from a line source on an inclined plane containing a topographic depression is studied using a lubrication model. The steady flow is perturbed by the depression. We focus on the regime in which the flow thickness is small relative to the lengthscale of the depression. For shallow depressions, the flow is only slightly perturbed. However, for deeper depressions a large pond of fluid with a horizontal free-surface is observed. This ponding of fluid is associated with the topography having uphill regions, which in the absence of inertia can only be surmounted by developing a deep fluid layer. The accumulation of fluid in the depression leads to a focusing of the flow, which is observed even far downstream of the depression.","PeriodicalId":369158,"journal":{"name":"Proceedings of the 22nd Australasian Fluid Mechanics Conference AFMC2020","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129598887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Abdulwahid, R. Situ, Richard J. Brown, Wenxian Lin
A wet scrubber is an air pollution removal device that eliminates particulate matter and acid gases from a diesel engine. The exhaust gas enters the scrubber beneath the liquid surface, causing a reduction in gas temperature and increases the relative humidity of scrubber outlet. In this study, bubble motion was captured with a high-speed video system in 16 test conditions. Heat transfer analysis was used to investigate the direct interaction between the bubbles and their surrounding liquid. The experimental results confirmed that there are three flow regions at the low inlet gas flow rate: inlet, bulk and exit region (at exit). At the departing region, the bubble diameter depended on the inlet gas volumetric flow rate. The bubble number ratio was a function of the inlet gas Reynolds number. The heat transfer between the bubbles and liquid depended on the inlet gas temperature ratio.
{"title":"Bubble Dynamics in a Diesel Exhaust Wet Scrubber","authors":"A. Abdulwahid, R. Situ, Richard J. Brown, Wenxian Lin","doi":"10.14264/93b2cf8","DOIUrl":"https://doi.org/10.14264/93b2cf8","url":null,"abstract":"A wet scrubber is an air pollution removal device that eliminates particulate matter and acid gases from a diesel engine. The exhaust gas enters the scrubber beneath the liquid surface, causing a reduction in gas temperature and increases the relative humidity of scrubber outlet. In this study, bubble motion was captured with a high-speed video system in 16 test conditions. Heat transfer analysis was used to investigate the direct interaction between the bubbles and their surrounding liquid. The experimental results confirmed that there are three flow regions at the low inlet gas flow rate: inlet, bulk and exit region (at exit). At the departing region, the bubble diameter depended on the inlet gas volumetric flow rate. The bubble number ratio was a function of the inlet gas Reynolds number. The heat transfer between the bubbles and liquid depended on the inlet gas temperature ratio.","PeriodicalId":369158,"journal":{"name":"Proceedings of the 22nd Australasian Fluid Mechanics Conference AFMC2020","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130044065","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Water is the main source of life for humans as our body is made up of over 60% of water. We require water that is clean and safe for mandatory purposes such as food production, consumption and sanitary purposes. In many regions of the world water scarcity is a serious concern. These regions, rely heavily on water purification methods such as desalination which purifies saline water from rivers and oceans, removing minerals and salts to give fresh water. The problem with current desalination methods is that they are overly costly and requiring sophisticated equipment, and thus not well suitable for undeveloped regions which often need desalination most. This experimental work reports on a more affordable and simpler (not requiring sophisticated equipment) desalination method through the use of simple materials as it would reduce significantly the cost of production and operation. The process of the prototype will be reverse osmosis which uses pressure to force water through a filter, trapping minerals and salts to give fresh water. The materials used will be sand and clay for the filter; and steel is used for the prototype’s structure. The composition of sand and clay that can act as the filter will be the challenge, as well as the amount of pressure required to force the water through the filter. The resultant product is an affordable and simple desalination method that can produce fresh water from saline water. This product will be easy to manufacture and use which would be suitable to most people of any skill and knowledge, especially in undeveloped regions, for obtaining fresh water.
{"title":"Desalination Using Simple Materials","authors":"D. To, B. P. Huynh","doi":"10.14264/5577c91","DOIUrl":"https://doi.org/10.14264/5577c91","url":null,"abstract":"Water is the main source of life for humans as our body is made up of over 60% of water. We require water that is clean and safe for mandatory purposes such as food production, consumption and sanitary purposes. In many regions of the world water scarcity is a serious concern. These regions, rely heavily on water purification methods such as desalination which purifies saline water from rivers and oceans, removing minerals and salts to give fresh water. The problem with current desalination methods is that they are overly costly and requiring sophisticated equipment, and thus not well suitable for undeveloped regions which often need desalination most. This experimental work reports on a more affordable and simpler (not requiring sophisticated equipment) desalination method through the use of simple materials as it would reduce significantly the cost of production and operation. The process of the prototype will be reverse osmosis which uses pressure to force water through a filter, trapping minerals and salts to give fresh water. The materials used will be sand and clay for the filter; and steel is used for the prototype’s structure. The composition of sand and clay that can act as the filter will be the challenge, as well as the amount of pressure required to force the water through the filter. The resultant product is an affordable and simple desalination method that can produce fresh water from saline water. This product will be easy to manufacture and use which would be suitable to most people of any skill and knowledge, especially in undeveloped regions, for obtaining fresh water.","PeriodicalId":369158,"journal":{"name":"Proceedings of the 22nd Australasian Fluid Mechanics Conference AFMC2020","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122870326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Abdulwahid, R. Situ, Richard J. Brown, Wenxian Lin
A wet scrubber is an air pollution removal device that eliminates particulate matter and acid gases from a diesel engine. The exhaust gas enters the scrubber beneath the liquid surface, causing a reduction in gas temperature and increases the relative humidity of the scrubber outlet. In this study, a wet scrubber was investigated experimentally based on a transient heat loss and steady-state heating process. A transient heat loss experiments were performed to estimate the heat loss from the scrubber surface. The steady-state heating process was investigated separately with various inlet gas temperatures and flow rates. The experimental results confirmed that the scrubber effectively reduces the inlet gas temperature from 650 oC to about 50oC. However, the outlet gas relative humidity increased due to the high liquid evaporation rate. A thermodynamic analysis estimated the outlet gas relative humidity and compares it with the measured values. The contribution of this study is: heat loss estimation methodology and relative humidity calculations.
{"title":"Thermodynamic Analysis of a Diesel Exhaust Wet Scrubber","authors":"A. Abdulwahid, R. Situ, Richard J. Brown, Wenxian Lin","doi":"10.14264/9b3f9c0","DOIUrl":"https://doi.org/10.14264/9b3f9c0","url":null,"abstract":"A wet scrubber is an air pollution removal device that eliminates particulate matter and acid gases from a diesel engine. The exhaust gas enters the scrubber beneath the liquid surface, causing a reduction in gas temperature and increases the relative humidity of the scrubber outlet. In this study, a wet scrubber was investigated experimentally based on a transient heat loss and steady-state heating process. A transient heat loss experiments were performed to estimate the heat loss from the scrubber surface. The steady-state heating process was investigated separately with various inlet gas temperatures and flow rates. The experimental results confirmed that the scrubber effectively reduces the inlet gas temperature from 650 oC to about 50oC. However, the outlet gas relative humidity increased due to the high liquid evaporation rate. A thermodynamic analysis estimated the outlet gas relative humidity and compares it with the measured values. The contribution of this study is: heat loss estimation methodology and relative humidity calculations.","PeriodicalId":369158,"journal":{"name":"Proceedings of the 22nd Australasian Fluid Mechanics Conference AFMC2020","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125588816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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