写udf，动网格DEFINE_CG_MOTION 疑问？

zhangload

（1）请问
有谁用udf做动网格
编写DEFINE_CG_MOTION(piston, dt, vel, omega, time, dtime)

成功过的？？

给个例子好吗？？

如有相关例子请发送到zhangload@163.com

（2）按照目前udf 做的移动移动网格问题的相关例子中的udf  如下，都是帮助文件里自带的例子。见附录，估计做相关的人都看过了这2个例子。有几点疑问：

     1）他们这些力的转换思路 和理论是什么？
     2）这2个例子的力学转换关系有些不同，为什么会这样？哪个是标准的？
     3）他们中给定的常数，比如，50.0 、K_SPRING 150000 、 0.4 * 0.0254  是什么含义？是如何得来？ 如果要修改一般要注意哪些？




附  udf例子－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－－
1)#include "udf.h"

static real v_prev = 0.0;

DEFINE_CG_MOTION(piston, dt, vel, omega, time, dtime)
{
  Thread *t;
  face_t f;
  real NV_VEC (A);
  real force, dv;

  /* reset velocities */
  NV_S (vel, =, 0.0);
  NV_S (omega, =, 0.0);

  if (!Data_Valid_P ())
    return;

  /* get the thread pointer for which this motion is defined */
  t = DT_THREAD (dt);

  /* compute pressure force on body by looping through all faces */
  force = 0.0;
  begin_f_loop (f, t)
    {
      F_AREA (A, f, t);
      force += F_P (f, t) * NV_MAG (A);
    }
  end_f_loop (f, t)

  /* compute change in velocity, i.e., dv = F * dt / mass
     velocity update using explicit Euler formula */
  dv = dtime * force / 50.0;
  v_prev += dv;
  Message ("time = %f, x_vel = %f, force = %f\n", time, v_prev,
  force);

  /* set x-component of velocity */
  vel[0] = v_prev;
}


+--------------------------------------------------------------------------------
2)DEFINE_CG_MOTION(valve, dt, cg_vel, cg_omega, time, dtime)
{
#if !RP_NODE
  Thread *t = DT_THREAD (dt);
  face_t f;
  real force, loc;
#endif
  real velo;

  /* reset velocities */
  NV_S (cg_vel, =, 0.0);
  NV_S (cg_omega, =, 0.0);

  if (!Data_Valid_P ())
    return;

#if !RP_NODE  
  /* compute force on piston wall */
  force = 0.0;
  begin_f_loop (f, t)
    {
      real *AA;

      AA = F_AREA_CACHE (f, t);
      force += F_P (f, t) * AA[0];
    }
  end_f_loop (f, t)

# if RP_2D
  if (rp_axi)
    force *= 2.0 * M_PI;
# endif

  read_loc_velo_file (&loc, &velo);

  /* add in spring force */
# define K_SPRING 150000
  {
    real init_disp = 0.4 * 0.0254;
    real s_force =  K_SPRING * (loc + init_disp);

    force = force - s_force;
  }

  /* compute change in velocity */
  {
    real dv = dtime * force / 0.01;

    velo += dv;
    loc += velo * dtime;
  }

  Message ("\nUDF valve: time = %f, x_vel = %f, force = %f, loc(m)= %f\n",
           time, velo, force, loc);
  write_loc_velo_file (loc, velo);
#endif /* !RP_NODE */

#if PARALLEL
  host_to_node_real_1 (velo);
#endif

  cg_vel[0] = velo;
}

hyacinth

动网格 UDF，支持多个运动，支持并行，支持信息自动保存

1. /* ******************************************* */
   
2. /* ******************************************* */
   
3. 
   
4. 可以根据需要，添加更多的运动
   
5. 支持多个运动，支持并行，支持信息自动保存
   
6. 
   
7. /* ******************************************* */
   
8. /* ******************************************* */
   
9. 
   
10. # include "udf.h"
    
11. 
    
12. /* ******************************************* */
    
13. static real G = 9.80; /* gravity */
    
14. 
    
15. static real valve_M = 0.1; /* mass of moving object*/
    
16. static real valve_S = 0.0; /* replacement of moving object*/
    
17. static real valve_V = 0.0; /* velocity of moving object */
    
18. static real valve_F = 0.0; /* fluid force of one component */
    
19. static int is_valve = 0; /* is the object still moving */
    
20. 
    
21. static real ball_M = 0.19; /* mass of moving object*/
    
22. static real ball_S = 0.0; /* replacement of moving object*/
    
23. static real ball_V = 0.0; /* velocity of moving object */
    
24. static real ball_F = 0.0; /* fluid force of one component */
    
25. static int is_ball = 0; /* is the object still moving */
    
26. /* ******************************************* */
    
27. 
    
28. DEFINE_CG_MOTION(valve, dt, vel, omega, time, dtime)
    
29. {
    
30. #if !RP_HOST
    
31.     Thread *t;
    
32.     Domain *d;
    
33.     real dv, CG[ND_ND], force[3], moment[3];
    
34. 
    
35.     /* Check to see if there is data */
    
36.     if (!Data_Valid_P ())
    
37.     {
    
38.         Message0("\n\nNo data->No mesh motion!!!\n\n");
    
39.         return;
    
40.     }
    
41.    
    
42.     /* Reset velocities */
    
43.     NV_S (vel, =, 0.0);
    
44.     NV_S (omega, =, 0.0);
    
45.    
    
46.     /* Calculate force*/
    
47.     d = THREAD_DOMAIN (DT_THREAD ((Dynamic_Thread *)dt));
    
48.     t = DT_THREAD(dt);
    
49.     NV_S (CG, =, 0.0);
    
50.     Compute_Force_And_Moment (d, t, CG, force, moment, FALSE);
    
51. 
    
52.     /* Compute change in velocity, i.e., dv=F*dt/M velocity update using explicit Euler formula */
    
53.     dv = dtime * (force[0] - G * valve_M) / valve_M;
    
54.     if(is_valve == 0 && dv >= 0.0)
    
55.     {
    
56.         is_valve = 1;
    
57.         Message0("\n\n============================== BEGIN VALVE MOTION INFO ==============================\n");
    
58.         Message0("\n VALVE BEGIN MOVE! \n");
    
59.         Message0("\n============================== END VALVE MOTION INFO ==============================\n");
    
60.     }
    
61.     if(is_valve == 0 && dv < 0.0) {
    
62.         dv = 0.0;
    
63.     }
    
64.     valve_V += dv;
    
65.     if(valve_S >= 0.010)
    
66.     {
    
67.         valve_V = 0.0;
    
68.     }
    
69.     valve_S += valve_V * dtime;
    
70. 
    
71.     /* Set x-component of velocity */
    
72.     vel[0] = valve_V;
    
73.     valve_F = force[0];
    
74. 
    
75.     Message0("\n\n============================== BEGIN VALVE MOTION INFO ==============================\n");
    
76.     Message0("\ntime=%.5e F(x)=%.4e S(x)=%.6e V(x)=%.6e move?=%d\n", time, force[0], valve_S, valve_V, is_valve);
    
77.     Message0("\n============================== END VALVE MOTION INFO ==============================\n");
    
78. #endif
    
79. 
    
80.     node_to_host_real_1(valve_S);
    
81.     node_to_host_real_1(valve_V);
    
82.     node_to_host_real_1(valve_F);
    
83.     node_to_host_int_1(is_valve);
    
84. 
    
85.     node_to_host_real(vel, ND_ND);
    
86.     node_to_host_real(omega, ND_ND);
    
87. }
    
88. 
    
89. DEFINE_CG_MOTION(ball, dt, vel, omega, time, dtime)
    
90. {
    
91. #if !RP_HOST
    
92.     Thread *t;
    
93.     Domain *d;
    
94.     real dv, CG[ND_ND], force[3], moment[3];
    
95. 
    
96.     /* Check to see if there is data */
    
97.     if (!Data_Valid_P ())
    
98.     {
    
99.         Message0("\n\nNo data->No mesh motion!!!\n\n");
    
100.         return;
     
101.     }
     
102.    
     
103.     /* Reset velocities */
     
104.     NV_S (vel, =, 0.0);
     
105.     NV_S (omega, =, 0.0);
     
106.    
     
107.     /* Calculate force*/
     
108.     d = THREAD_DOMAIN (DT_THREAD ((Dynamic_Thread *)dt));
     
109.     t = DT_THREAD(dt);
     
110.     NV_S (CG, =, 0.0);
     
111.     Compute_Force_And_Moment (d, t, CG, force, moment, FALSE);
     
112. 
     
113.     /* Compute change in velocity, i.e., dv=F*dt/M velocity update using explicit Euler formula */
     
114.     dv = dtime * (force[0] - G * ball_M) / ball_M;
     
115.     if(is_ball == 0 && dv >= 0.0)
     
116.     {
     
117.         is_ball = 1;
     
118.         Message0("\n\n============================== BEGIN BALL MOTION INFO ==============================\n");
     
119.         Message0("\n BALL BEGIN MOVE! \n");
     
120.         Message0("\n============================== END BALL MOTION INFO ==============================\n");
     
121.     }
     
122.     if(is_ball == 0 && dv < 0.0) {
     
123.        dv = 0.0;
     
124.     }
     
125.     ball_V += dv;
     
126.     ball_S += ball_V * dtime;
     
127.    
     
128.     /* Set x-component of velocity */
     
129.     vel[0] = ball_V;
     
130.     ball_F = force[0];
     
131. 
     
132.     Message0("\n\n============================== BEGIN BALL MOTION INFO ==============================\n");
     
133.     Message0("\ntime=%.5e F(x)=%.4e S(x)=%.6e V(x)=%.6e move?=%d\n", time, force[0], ball_S, ball_V, is_ball);
     
134.     Message0("\n============================== END BALL MOTION INFO ==============================\n\n");
     
135. #endif
     
136. 
     
137.     node_to_host_real_1(ball_S);
     
138.     node_to_host_real_1(ball_V);
     
139.     node_to_host_real_1(ball_F);
     
140.     node_to_host_int_1(is_ball);
     
141. 
     
142.     node_to_host_real(vel, ND_ND);
     
143.     node_to_host_real(omega, ND_ND);
     
144. }
     
145. 
     
146. static void write_data(FILE *fp)
     
147. {
     
148.     fprintf(fp, "%e ", valve_V);
     
149.     fprintf(fp, "\n");
     
150.     fprintf(fp, "%e ", valve_S);
     
151.     fprintf(fp, "\n");
     
152.     fprintf(fp, "%e ", valve_F);
     
153.     fprintf(fp, "\n");
     
154.     fprintf(fp, "%d ", is_valve);
     
155.     fprintf(fp, "\n");
     
156. 
     
157.     fprintf(fp, "%e ", ball_V);
     
158.     fprintf(fp, "\n");
     
159.     fprintf(fp, "%e ", ball_S);
     
160.     fprintf(fp, "\n");
     
161.     fprintf(fp, "%e ", ball_F);
     
162.     fprintf(fp, "\n");
     
163.     fprintf(fp, "%d ", is_ball);
     
164. }
     
165. 
     
166. static void read_data(FILE * fp)
     
167. {
     
168.     fscanf(fp, "%e", [$valve_V)]
     
169.     fscanf(fp, "%e", [$valve_S)]
     
170.     fscanf(fp, "%e", [$valve_F)]
     
171.     fscanf(fp, "%d", [$is_valve)]
     
172. 
     
173.     fscanf(fp, "%e", [$ball_V)]
     
174.     fscanf(fp, "%e", [$ball_S)]
     
175.     fscanf(fp, "%e", [$ball_F)]
     
176.     fscanf(fp, "%d", [$is_ball)]
     
177. }
     
178. 
     
179. DEFINE_RW_FILE(reader, fp)
     
180. {
     
181.     Message0("\n\n============================== BEGIN UDF INFOMATION ==============================\n");
     
182.     Message0("\nReading UDF data from data file...\n");
     
183. 
     
184. #if PARALLEL
     
185. #if RP_HOST
     
186.     read_data(fp);
     
187. #endif
     
188. #else
     
189.     read_data(fp);
     
190. #endif
     
191. 
     
192.     host_to_node_real_1(valve_V);
     
193.     host_to_node_real_1(valve_S);
     
194.     host_to_node_real_1(valve_F);
     
195.     host_to_node_int_1(is_valve);
     
196.    
     
197.     host_to_node_real_1(ball_V);
     
198.     host_to_node_real_1(ball_S);
     
199.     host_to_node_real_1(ball_F);
     
200.     host_to_node_int_1(is_ball);
     
201. 
     
202.     Message0("\n------------------------------ BEGIN VALVE MOTION INFO ------------------------------\n");
     
203.     Message0("\nS(x)=%.6e V(x)=%.6e F(x)=%.4e move?=%d\n", valve_S, valve_V, valve_F, is_valve);
     
204.     Message0("\n------------------------------ END VALVE MOTION INFO ------------------------------\n");
     
205.    
     
206.     Message0("\n------------------------------ BEGIN BALL MOTION INFO ------------------------------\n");
     
207.     Message0("\nS(x)=%.6e V(x)=%.6e F(x)=%.4e move?=%d\n", ball_S, ball_V, ball_F, is_ball);
     
208.     Message0("\n------------------------------- END BALL MOTION INFO -------------------------------\n");
     
209.     Message0("\n================================ END UDF INFOMATION ================================\n\n");
     
210. }
     
211. 
     
212. DEFINE_RW_FILE(writer, fp)
     
213. {
     
214.     Message0("\n\n============================== BEGIN UDF INFOMATION ==============================\n");
     
215.     Message0("\n\nWriting UDF data to data file...\n");
     
216. 
     
217. #if PARALLEL
     
218. #if RP_HOST
     
219.     write_data(fp);
     
220. #endif
     
221. #else
     
222.     write_data(fp);
     
223. #endif
     
224.     Message0("\n================================ END UDF INFOMATION ================================\n\n");
     
225. }

复制代码

来自傲雪

albert

我觉得我们自己做的时候不用这么麻烦把
直接做动网格的那部分就可以乐把

snow2146073

学不会啊，愁啊

漂亮朋友

基本理论是牛顿第二定律，50是质量，K_spring 代表弹簧刚度值，0.4（inch） * 0.0254  表示长度（因为ＵＤＦ采用国际单位制），关于ＵＤＦ的使用方法主要靠自己好好琢磨，鉴于你用ＣＧ——ｍｏｔｉｏｎ，推荐你几个宏，１，ＤＴ＿ＣＧ（ｄｔ）２．ＣＯＭＰＵＴＥ＿ＦＯＲＣＥ＿ＡＮＤ＿ＭＯＭＥＮＴ．

zczhang1989

有没有谁知道那个光顺法的那个怎么让动边界的位移扩散出去。

Seventy721

需要将周边的区域也设置为动网格，可以在GUI界面里Dynamic zones里面设置好参数，然后在UDF里用SET_DEFORMING_THREAD_FLAG(THREAD_T0(t));

ljxronaldo

回复 5 # 漂亮朋友 的帖子

请问F_AREA_CACHE 是什么意思呢？
另外，你提供的宏是从哪儿找到的，有没有什么参考资料提供一下啊。谢谢！
190745256@qq.com