Q2. What have the authors stated for future works in "Comparison between 2.5-d and 3-d realistic models for wind field adjustment " ?
However, though such differences are small, further research is needed in order to construct new wind profiles that exactly satisfy all the available measures of wind velocities. However, further considerations should be taken into account in future works for a better performance of the models. For example, a finer map of roughness, a more sophisticated interpolation of wind velocities, a better approximation of the friction coefficient and a greater number of measurement stations well distributed over the studied region will help to reduce the errors of the models.
Q3. What is the way to obtain an accurate windfield in zones with very steep slopes?
In order to obtain an accurate windfield in zones with very steep slopes, the mesh should be adapted to the contour lines, since a change in the direction of edges in the mesh may strongly affect the computed wind.
Q4. What are some of the main problems of wind models?
Wind models are interesting tools to the study of several problems related to the atmosphere, such as, the effect of wind on structures, pollutant transport [26], fire spreading [19], wind farm location, etc.
Q5. How many repetitions of the parameter setting of each hour should be done?
It is evident that, in order to avoid spurious solutions, more than 20 repetitions for parameter setting of each hour should be done.
Q6. What is the main reason for the periodic updating of the main parameters of the models?
The periodic updating of the main parameters of the models has proved to be fundamental for reducing the errors of the computed wind.
Q7. What is the solution of the optimal control problem?
Vi ∥ ∥ ∥ ∥ 2+ α2∫∂ω v2 (20)where ρǫ,i is a suitable smoothing function given for example byρǫ,i(x) = 1ǫ2 ρ( x − xi ǫ )ρ(x) = {Me− 1 1−||x||2 for ||x|| < 10 for ||x|| ≥ 1for a small ǫ and M such that ∫ρǫ,i(x)dx = 1The optimal control problem to be solved is posed as follow: Find u ∈ V such thatJ(u) = inf v∈V J(v) (21)The solution u of the optimal control problem (21) is characterized by J ′(u) = 0.Using the general optimal control theory [15], and introducing the adjoin state, then the problem (21) is characterized by the following three equations relating p , q and u:• ∫ω a∇p(u) · ∇ϕ+1α∫∂ω qϕ = −∫ω b∇t̂ · ∇ϕ ∀ϕ (22)• ∫ω a∇q(u) · ∇ψ− N ∑i=1∫ω ρǫ,i(m∇p(u) + n∇t̂− Vi)m · ∇ψ = 0 ∀ψ (23)•u = − 1α q on ∂ω (24)There exist a unique solution of the problem (9).
Q8. How do the authors calculate the height and the roughness length of the mesh?
Once the authors have interpolated the height and the roughness length in the nodes of these refined two-dimensional mesh, the authors use the derefinement algorithm [9,31] described in section 5.1 with εh = 10m and εr = 0.01m, keeping in any case the nodes located inside the six circles.
Q9. What makes the models attractive from the practical point of view?
The relative simplicity of diagnostic models makes them attractive from the practical point of view, since they do not require many input data and may be easily used.
Q10. What is the purpose of the mesh?
The use of their refinement/derefinement process in the 2-D mesh corresponding to the terrain surface allows us to obtain meshes that are accurately adapted to different functions as well as are locally refined around several points.
Q11. What is the definition of the intensity of turbulence?
The intensity of turbulence i is defined as the square root of the sum of variances σ21 , σ 2 2, σ 2 3 , of the three components of the velocity U 0 1 , U 0 2 , U 0 3 ,respectively, divided by the average wind velocity that has been measured,i =√σ21 + σ 2 2 + σ 2 3||U0|| (51)However, only measures of speed variations are often available but not of the wind direction.
Q12. What is the technique for constructing tetrahedral meshes?
The authors have used a technique for constructing tetrahedral meshes which are simultaneously adapted to the terrain orography and the roughness length.
Q13. What is the importance of the horizontal distance from each point to the measurement stations?
For ε → 1, the importance of the horizontal distance from each point to the measurement stations is greater, while ε → 0 signifies more importance of the height difference between each point and the measurement stations.
Q14. How many measures are available at the same vertical line?
In addition, since several measures are often available at the same vertical line, the authors have constructed a least square adjustment of such measures for developing a vertical profile of wind velocities from an optimum friction velocity.