An Idealized 3D Model of Interfacial Instability of Aeolian Bedform
An idealized morphodynamic model is constructed for formation of the aeolian sand ripples from small bottom perturbations of a two-dimensional sand bed. The main goal of the analysis is to evaluate the influence of the gravity flow (including “impact-induced gravity flow” in the reptation flux and “...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2021-09-01
|
| Series: | Applied Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2076-3417/11/19/8956 |
| _version_ | 1827680991291899904 |
|---|---|
| author | Peng Wang Jie Zhang Ning Huang |
| author_facet | Peng Wang Jie Zhang Ning Huang |
| author_sort | Peng Wang |
| collection | DOAJ |
| description | An idealized morphodynamic model is constructed for formation of the aeolian sand ripples from small bottom perturbations of a two-dimensional sand bed. The main goal of the analysis is to evaluate the influence of the gravity flow (including “impact-induced gravity flow” in the reptation flux and “topography-induced gravity flow” in the creep flux) on the formation of the aeolian sand ripples and to clarify the relative contribution of various factors to the bed instability. A 3D linear stability analysis reveals that gravity flow appreciably affects the dynamics behaviors of aeolian sand ripples, which decreases the growth rate of sand ripples, tends to stabilize the sand bed, and leads to longer wavelength. We found that the competition between the destabilizing effect of reptation flow and the stabilizing effects of gravity flow leads to pattern selection. The along-crest diffusion of topography driven by impact and gravity is beneficial to the transverse stability of sand ripples, producing sand ripples with straighter and more continuous crests. For moderate values of <i>D</i>, the most unstable mode has zero value of the transverse wavenumber (<i>k<sub>y</sub></i> = 0), thus corresponding to aeolian ripples with crests perpendicular to the wind. Moreover, when the impact angle is 9–16°, it has little effect on the characteristics of sand ripples for the initial stage of ripple development. For every increase of the impact angle by 1°, the initial wavelength only increases by about 1.5%. In conclusion, the influence of the gravity flow on the dynamics of sand ripples formation stage cannot be neglected. |
| first_indexed | 2024-03-10T07:07:05Z |
| format | Article |
| id | doaj.art-ce1c7134035b4adea14a62bbeeed7b90 |
| institution | Directory Open Access Journal |
| issn | 2076-3417 |
| language | English |
| last_indexed | 2024-03-10T07:07:05Z |
| publishDate | 2021-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Applied Sciences |
| spelling | doaj.art-ce1c7134035b4adea14a62bbeeed7b902023-11-22T15:45:37ZengMDPI AGApplied Sciences2076-34172021-09-011119895610.3390/app11198956An Idealized 3D Model of Interfacial Instability of Aeolian BedformPeng Wang0Jie Zhang1Ning Huang2School of Science, Lanzhou University of Technology, Lanzhou 730050, ChinaKey Laboratory of Mechanics on Disaster and Environment in Western China, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou 730000, ChinaKey Laboratory of Mechanics on Disaster and Environment in Western China, College of Civil Engineering and Mechanics, Lanzhou University, Lanzhou 730000, ChinaAn idealized morphodynamic model is constructed for formation of the aeolian sand ripples from small bottom perturbations of a two-dimensional sand bed. The main goal of the analysis is to evaluate the influence of the gravity flow (including “impact-induced gravity flow” in the reptation flux and “topography-induced gravity flow” in the creep flux) on the formation of the aeolian sand ripples and to clarify the relative contribution of various factors to the bed instability. A 3D linear stability analysis reveals that gravity flow appreciably affects the dynamics behaviors of aeolian sand ripples, which decreases the growth rate of sand ripples, tends to stabilize the sand bed, and leads to longer wavelength. We found that the competition between the destabilizing effect of reptation flow and the stabilizing effects of gravity flow leads to pattern selection. The along-crest diffusion of topography driven by impact and gravity is beneficial to the transverse stability of sand ripples, producing sand ripples with straighter and more continuous crests. For moderate values of <i>D</i>, the most unstable mode has zero value of the transverse wavenumber (<i>k<sub>y</sub></i> = 0), thus corresponding to aeolian ripples with crests perpendicular to the wind. Moreover, when the impact angle is 9–16°, it has little effect on the characteristics of sand ripples for the initial stage of ripple development. For every increase of the impact angle by 1°, the initial wavelength only increases by about 1.5%. In conclusion, the influence of the gravity flow on the dynamics of sand ripples formation stage cannot be neglected.https://www.mdpi.com/2076-3417/11/19/8956aeolian transportimpact-induced gravity flowaeolian rippleswind erosioninstability |
| spellingShingle | Peng Wang Jie Zhang Ning Huang An Idealized 3D Model of Interfacial Instability of Aeolian Bedform Applied Sciences aeolian transport impact-induced gravity flow aeolian ripples wind erosion instability |
| title | An Idealized 3D Model of Interfacial Instability of Aeolian Bedform |
| title_full | An Idealized 3D Model of Interfacial Instability of Aeolian Bedform |
| title_fullStr | An Idealized 3D Model of Interfacial Instability of Aeolian Bedform |
| title_full_unstemmed | An Idealized 3D Model of Interfacial Instability of Aeolian Bedform |
| title_short | An Idealized 3D Model of Interfacial Instability of Aeolian Bedform |
| title_sort | idealized 3d model of interfacial instability of aeolian bedform |
| topic | aeolian transport impact-induced gravity flow aeolian ripples wind erosion instability |
| url | https://www.mdpi.com/2076-3417/11/19/8956 |
| work_keys_str_mv | AT pengwang anidealized3dmodelofinterfacialinstabilityofaeolianbedform AT jiezhang anidealized3dmodelofinterfacialinstabilityofaeolianbedform AT ninghuang anidealized3dmodelofinterfacialinstabilityofaeolianbedform AT pengwang idealized3dmodelofinterfacialinstabilityofaeolianbedform AT jiezhang idealized3dmodelofinterfacialinstabilityofaeolianbedform AT ninghuang idealized3dmodelofinterfacialinstabilityofaeolianbedform |