Configuration of Mike21 for the simulation of nearshore storm waves, currents and sediment transport: Brackley Bight, Prince Edward Island

Abstract

The North Shore of Prince Edward Island (PEI) is a sandy, multi-barred coast with limited fetch in most directions but open to the Gulf of St. Lawrence for several hundred kilometres to the north. In the fall and winter, storms tracking northwards across PEI and into the Gulf can bring sustained storm waves which generate currents capable of transporting sand in both the along- and across-shore directions. Mike21 is a commercially available combined wave, hydrodynamic and sand transport model that may be utilised to improve understanding of contemporary sand transport and possible implications of changing climate in the Brackley Bight area of the North Shore. This manuscript describes the development of a Mike21 model domain and optimal configurations of the Mike21 Spectral Wave, Hydrodynamic and Sand Transport modules appropriate to the study area. The sensitivities of several parameters in each module are tested. The Spectral Wave and Hydrodynamic modules are sensitive to estimates of bed roughness with optimal values considerably lower than published semi-empirical estimates. The Sand Transport module is sensitive to the input sediment transport tables and estimates of the maximum amount of vertical bed level change per day. Simulation of a 4-day moderate northeasterly storm is conducted and the results are compared to currents, waves, and tides measured by S4 current meters and the instrumented seabed lander RALPH during a sediment transport experiment in 1999. The model successfully simulates storm waves and currents and provides reasonable estimates of the amount and patterns of sediment transport.

Dynamic beach response to changing storminess of Unst, Shetland: implications for landing places exploited by Norse communities

“…Numerical sediment transport modelling was undertaken using MIKE21 (well-developed modelling software used in a variety of coastal scientific and engineering studies, e.g. Siegle et al, 2004;Manson, 2012;Houser, 2013;Vincinanza et al, 2013) to quantify the ability for both embayments to accumulate stable nearshore sediment supplies and thus form beaches. The differing geomorphic complexity of both embayments presents an interesting challenge.…”

Sediment accumulation in embayments controlled by bathymetric slope and wave energy: Implications for beach formation and persistence

“…This model was chosen because more than 20 years of development has produced a robust and reliable tool for coastal engineering studies (Siegle et al, 2004;Manson, 2012;Houser, 2013;Vicinanza et al, 2013;DHI, 2014;Contestabile et al, 2015). This model was chosen because more than 20 years of development has produced a robust and reliable tool for coastal engineering studies (Siegle et al, 2004;Manson, 2012;Houser, 2013;Vicinanza et al, 2013;DHI, 2014;Contestabile et al, 2015).…”

“…To better understand our semi-quantitative observations and explore the potential role of bathymetry and coastal sediment transport in dictating the presence or absence of embayed beaches, we performed simulations of the evolution of idealised headland embayments using the MIKE21 coupled hydrodynamic and morphodynamic model. This model was chosen because more than 20 years of development has produced a robust and reliable tool for coastal engineering studies (Siegle et al, 2004;Manson, 2012;Houser, 2013;Vicinanza et al, 2013;DHI, 2014;Contestabile et al, 2015). The two-dimensional hydrodynamic (HD) and sand transport (ST) modules were coupled, and hydrodynamics were forced by the spectral wave (SW) module, which was run independently to calculate wind-generated waves and wave radiation stresses as an input for the HD module.…”

“…The open boundary was set so that the spatial change in sediment flux across the boundary was zero. This allowed sediment to both enter and leave the domain as demanded by the changing hydrodynamic conditions, without suddenly depositing or eroding material at the boundary, avoiding a glass wall effect (Keen et al, 2003;Manson, 2012). We chose this boundary condition to avoid artificial accumulation of sediment against the boundary.…”

Assessment of the Impact of Breakwater on Erosion-Deposition Processes in Tam Quan River Mouth, Binh Dinh Province

“…Bản thân DHI đã có nhiều dự án để kiểm chứng các mô hình của mình. Có thể kể đến: Mô phỏng các trường thủy động lực ở vịnh Mele và cảng Vila, Vanuatu[2]; Xác định tốc độ lắng đọng trong cảng Bakkafjõru cũng như độ sâu ổn định trong và ngoài cửa luồng dẫn vào cảng[3]; Cài đặt MIKE 21 để mô phỏng sóng bão gần bờ, dòng chảy và di chuyển trầm tích tại Brackley Bight phía bắc đảo Prince Edward[4]; Tính toán bồi xói luồng tàu do tác dụng của dòng chảy và đảm bảo kết quả tính được chính xác cho vùng nghiên cứu, khu vực tính toán được mở rộng tới vĩ độ 15 o 13'N về phía bắc và 13 o 56'N xuống phía nam. Về phía biển vùng tính toán được mở rộng ra tới kinh tuyến Với vùng tính đó, đã thiết lập lưới tính với 7333 phần tử tam giác (hình 1a).Với những khu vực ngoài khơi hay vùng ven bờ có đường bờ đơn giản, phần tử lưới được làm thô.…”